Curable coating material for non-impact printing

ABSTRACT

A non-impact printing device ( 301 ) comprising: a coating material ( 237 ) being curable and comprising a resin; the coating material comprising an amorphous resin portion in an amount of at least 30 w-% based on the overall amount of resin and comprising with respect to the entire amount of coating material less than 0.5 w-% of flow additive; a printing unit, in particular an electrophotographic printing unit, being configured for printing the coating material ( 237 ) so as to form a coating layer, wherein the coating layer forms at least part of a layer package comprising at least one layer; the non-impact printing device being configured for providing the layer package so as to define a surface structure with the layer package; wherein the surface structure is defined by a thickness variation of the layer package; wherein the thickness variation is in a range between 1 μm and 1000 μm, in particular in a range between 1 and 300 μm, and is in particular more than 1 μm, in particular more than 5 μm, in particular more than 10 μm and in particular more than 20 μm.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a National Phase Patent Application of InternationalPatent Application Number PCT/EP2018/056139, filed on Mar. 13, 2018,which claims priority of European Patent Application Nos. 17160701.3,filed Mar. 13, 2017; 17161938.0, filed Mar. 20, 2017; and 17186011.7,filed Aug. 11, 2017. The entire contents of all of which areincorporated herein by reference.

FIELD OF INVENTION

The present invention relates to the field of coatings.

BACKGROUND

EP2 140 307 B1 relates to a process for applying a powder coating onto asubstrate. A transfer sheet is provided with a printed powder coating,wherein the printed powder coating is a thermosetting powder coatingcomposition which comprises a resin and a curing agent for the resin.The transfer sheet is then applied onto the substrate with the powdercoating in contact with the substrate. Thereafter the adherence of thepowder coating to the substrate is increased by heating the powdercoating to a temperature above its melt temperature but substantiallybelow its curing temperature, followed by removal of the transfer sheetfrom the powder coating and curing the powder coating on the substrate.A characteristic feature of the process is that the transfer sheet isremoved from the powder coating before the powder coating is cured. Thedeposition part of the process, comprising the steps of applying thetransfer sheet onto the substrate with the powder coating in contactwith the substrate and removing the transfer sheet from the powdercoating, may be repeated as many times as desired, followed by thensubjecting the entire decorated substrate to a curing step.

US2008/0241415 A1 and US2005/0202164 A1 relate to a powder coatingapparatus and a method of powder coating using an electromagnetic brush.

U.S. Pat. No. 6,342,273 B1 relates to a process for coating a substratewith a powder paint composition.

EP2 296 046 A1 relates to curable toner compositions and processes.

EP0 895 552 relates to a process for coating a board- or paper-likesubstrate with a powder paint composition.

US2010/0331456 A1 relates to a powder coating composition with newpigment.

US2008/0069606 A1 relates to an image forming method and image formingapparatus.

SUMMARY

In view of the above-described situation, there still exists a need foran improved technique that enables to provide a curable coating, inparticular a curable powder coating with improved characteristics.

This need may be met by the subject matter according to the independentclaims. Advantageous embodiments of the herein disclosed subject matterare described by the respective dependent claims.

It is noted that generally herein the term “in particular” denotesoptional features.

According to an aspect of the herein disclosed subject matter there isprovided a coating material.

According to an aspect of the herein disclosed subject matter, there isprovided a method, in particular a method of processing a coatingmaterial, a method of providing a transfer element, etc.

According to a further aspect of the herein disclosed subject matterthere is provided a processing device.

According to a further aspect of the herein disclosed subject matter, areservoir is provided.

According to a further aspect of the herein disclosed subject matter, adeveloper is provided. Unless stated differently, herein a reference toa developer is a reference to a respective material (i.e. a developermaterial generally comprising at least one carrier and at least onecoating material/toner).

According to a further aspect of the herein disclosed subject matter, atransfer element is provided.

According to a further aspect of the herein disclosed subject matter, asubstrate is provided.

According to a further aspect of the herein disclosed subject matter,there is provided a coating layer application device.

According to a further aspect of the herein disclosed subject matter,there is provided a computer program product, in particular a computerprogram product comprising a program element.

According to a further aspect of the herein disclosed subject matter, aprinting device, in particular a non-impact printing device or an offsetprinting device is provided. Non-impact printing (NIP) includes inparticular ink-jet printing, electrophotography, ionography,magnetography, thermoprint.

According to a further aspect of the herein disclosed subject matter, aprinted image is provided.

It is noted that in some embodiments features have been denoted withreference signs wherein in other embodiments, the reference signs areprovided for at least some features. Presence or absence of referencesigns shall in any way not be construed as limiting the disclosure ofthe herein disclosed subject matter and shall in no way be construed aslimiting in particular the claims.

It is further noted that any percentage provided herein shall beconsidered a weight percentage and shall be considered as being based onthe overall (entire) coating material (i.e. on weight of the overallcoating material) where applicable and where not explicitly indicatedotherwise. In this regard, terms like “with respect to”, “based on”,“with regard to” are considered synonymous herein. Weight percent is insome cases abbreviated by “w-%” (weight percent (or weight %)=w-%).Further abbreviations used herein are: micrometer=μm; millimeter=mm;lines per millimeter=l/mm; nanometer=nm; dots per inch=DPI, non-impactprinting=NIP; hour=h; minute=min; second=s; Kelvin=K, degrees Celcius=°C.; ultraviolet radiation=UV or UV radiation.

It is further noted that herein a reference to a glass transitiontemperature Tg shall be considered as reference to the glass transitiontemperature of the uncured coating material if not otherwise stated.According to an embodiment, the glass transition temperature (Tg) of thepolymers is determined by differential scanning calorimetrie (DSC)measurements with a heating and cooling rate of 20 K/min. According to afurther embodiment, the glass transition temperature is determined basedon ISO 11357-2. According to a further embodiment, the polymers arefirst heated from 25° C. to 80° C., the temperature hold for 1 minute,cooled to 20° C. and the temperature hold for 1 minute again (20 K/min).In a second step the polymers were heated to 130° C. which was used fordetermination of the Tg (20 K/min). The Tg is determined by evaluatingthe point of onset of the endothermal step.

In the context of the present technology, the term “about” incombination with a numerical value means in particular within a range ofplus and minus 10% with respect to the given value. For instance, “about6 μm” means preferably within a range of 5.4 μm to 6.6 μm.

Further, it is noted that herein any overlapping ranges specified forthe same quantity in some embodiments (e.g. for Tg: range 1=between 40°C. and 60° C. and range 2=between 50° C. and 70° C.) shall define interalia also any partial range or combined range derivable from thespecified boundaries (i.e. in the given example “between 40° C. and 60°C.”, “between 40° C. and 50° C.”, “between 40° C. and 70° C.”, “between50° C. and 60° C.”, “between 50° C. and 70° C.”, “between 60° C. and 70°C.”, etc.). This applies for overlapping closed ranges (as given in theexamples), overlapping open ranges (e.g. at least 50° C., at least 60°C., thus including also a range between 50° C. and 60° C.) as well asfor one or more open range overlapping with one or more closed range.

In the context of the present technology, the term “hydroxyl number” orhydroxyl value is the value which is preferably defined as the number ofmilligrams (mg) of potassium hydroxide required to neutralize the aceticacid taken up on acetylation of one gram of a chemical substance thatcontains free hydroxyl groups. The hydroxyl value is a measure of thecontent of free hydroxyl groups in a chemical substance, usuallyexpressed in units of the mass of potassium hydroxide (KOH) inmilligrams equivalent to the hydroxyl content of one gram of thechemical substance. The analytical method used to determine hydroxylvalue preferably involves acetylation of the free hydroxyl groups of thesubstance with acetic anhydride in pyridine solvent. After completion ofthe reaction, water is added, and the remaining unreacted aceticanhydride is converted to acetic acid and measured by titration withpotassium hydroxide.

In the context of the present technology, the term “acid number” or acidvalue is preferably defined as the mass of potassium hydroxide (KOH) inmilligrams that is required to neutralize one gram of chemicalsubstance. The acid number is a measure of the amount of carboxylic acidgroups in a chemical compound, such as a fatty acid, or in a mixture ofcompounds. In a typical procedure, a known amount of sample dissolved inorganic solvent (preferably isopropanol), is titrated with a solution ofpotassium hydroxide (KOH) with known concentration and withphenolphthalein as a color indicator.

In the context of the present technology, a portion of the substratesurface, which the powder coating is placed on, can be construed asdefining a plane spanned by an x-direction and a y-direction. Thez-direction is then the direction perpendicular to this plane, i.e. thedirection perpendicular to the plane defined by the substrate surfaceportion.

Analogously, the surface of one of multiple layers of powder coatingwhich are placed on the substrate surface can be construed as defining aplane spanned in an x-direction and a y-direction.

In the context of the present technology, the term “lateral” preferablyrefers to the x-direction and y-direction or, stated differently, theposition within the plane defined by the corresponding portion on thesubstrate surface. The term “height” preferably refers to thez-direction, or stated differently the position perpendicular to theplane defined by the substrate surface.

In the context of the present technology, the term “derivative” meanspreferably any compound that can be imagined to arise from anothercompound, if one atom or group of atoms is replaced with another atom orgroup of atoms. Stated differently, the term “derivative” meanspreferably a structural analog. Alternatively or additionally, the term“derivative” is used in the context of the present technology forcompounds that can be derived at least theoretically and/or can actuallybe derived by a chemical reaction from the compound that is referred toand/or can be theoretically or by an actual chemical reaction be derivedfrom a common precursor of the compound which is referred to.

Powder coating is applied mostly as a dry powder on a variety ofsubstrate surfaces. In contrast to conventional liquid paint, powdercoating does not require a solvent while the powder may be athermoplastic or a thermoset polymer. The coating is typically appliedwith a spray gun electrostatically and/or an airflow and is then curedunder heat resulting in a hard finish that is tougher than conventionalpaint. Powder coating may be used in a wide variety of technologicalfields and applications such as household appliances, automobile orbicycle parts. Powder coatings provide advantages as no solvents arerequired and, hence, negligible amounts of Volatile Organic Compounds(VOC) are released into the atmosphere, if any at all. Further, bypowder coatings thicker coatings than conventional coatings can beobtained. Powder coated items generally have only very few appearancedifferences between horizontally coated surfaces and vertically coatedsurfaces.

However, so far powder coating is used for providing a coating ofrelatively extended surfaces without selectively providing a specificcoating pattern or image on the coated surface. The herein describedtechnology is based on the idea of combining the advantages of a powdercoating process with a non-impact printing process carried out by anon-impact printing device. The herein described technology allows forrealizing the advantages of powder coating also for high resolutioncontour patterns and printed images on a variety of substrates.

The following chapters provide embodiments for one or more of the aboveidentified aspects of the herein disclosed subject matter wherein atleast some of the chapters focus on particular views on the hereindisclosed subject matter. Nevertheless, the embodiments under all viewsdescribe embodiments of the herein disclosed subject matter, inparticular of common aspects and in particular of the above definedaspects. It should be understood that any embodiments disclosed withregard to a particular chapter or aspect may of course also combinedwith embodiments of other chapters and/or aspects.

Further, it is noted that advantageous embodiments are defined bycombining a general aspect disclosed herein with one or more embodimentsdescribed herein, for example with one or more embodiments of a singlechapter.

Chapter 1

In the case of common toner systems as known from the state of the art,the toner particles usually show only a relatively poor adherence to thesubstrate surface, in particular in the case of surfaces which are dueto their intended use under mechanical stress and exposed to abrasiveenvironmental influences. Further problems can be seen in the relativelylow stability of the material against solvents or other chemicalsubstances as well as environmental influences. It follows from theabove stated, that the applicability of materials so far known from thestate of the art is restricted.

It is therefore an object of the present application to provide systemswhich provide suitable resistance and stability against abrasive effectsdue to harsh weather conditions and/or mechanical stress, stabilityagainst chemical substances such as chemical solvents, stability againstelectromagnetic radiation, in particular ultraviolet radiation, and atthe same time allow for a high resolution, sufficient hardness andexcellent adherence to a variety of substrate surfaces.

In this context it should be noted that common coating powdercompositions as used for powder coating in industrial applications arenot suitable for non-impact printing. Therefore, the claimedsubject-matter advantageously combines both, the concept of non-impactprinting as well as the concept of coating powders profiting from theadvantages of both technical fields while the same time avoiding theirrespective disadvantages.

In an embodiment, the formation of micro-scale droplets is avoided.Among the disadvantages, which result from the formation of micro scaledroplets, are the deterioration of the printed image due to forces whichresult from the presence of said micro-scale droplets.

According to an embodiment a coating material, in particular for digitalprinting, is provided, the coating material comprising: a resincomprising at least one resin component, in particular at least one typeof resin, the resin comprising in particular an amorphous resin portion;a curing agent comprising in particular at least one crosslinking agentand/or at least one initiator (e.g. at least one thermal initiatorand/or at least one photoinitiator) and/or at least one catalyst; andwherein the cured coating material comprises the curing agent in anamount such that the cured coating material is able to reach a rating ofat least 2-3 in the Methylethylketone test after 10 s according to theDIN EN 12720 and/or the cured coating material resists at least 50 IPA(Isopropyl alcohol) double rubs. According to an embodiment, theinitiator is a thermal initiator or an UV initiator.

According to an embodiment, one acetone or IPA double rub is meant oneback and forward movement over the surface of a coating having athickness of approximately 60 μm using a cotton cloth drenched inacetone or IPA, which cotton cloth covers a hammer head having a weightof 980 gram and a contact surface area with the coating of 2 cm2. Every20 rubs the cloth is drenched in acetone or IPA. The measurement iscontinued until the coating is removed (and the obtained DR (double rub)number is noted down) or until 100 DR are reached.

According to an embodiment, the resin (or the coating material)comprises one or more of the following:

-   -   (i) a polyester resin component containing with respect to the        overall amount of incorporated acid monomers-groups, at least 5        w-% isophthalic acid, in particular at least 10 w-% isophthalic        acid, further in particular at least 25 w-% isophthalic acid,        further in particular at least 30 w-% isophthalic acid, further        in particular at least 50 w-% isophthalic acid, further in        particular at least 80 w-% isophthalic acid, further in        particular at least 85 w-% isophthalic acid;

(ii) a polyester resin component containing 1 to 100 wt-% ofcycloaliphatic glycol compounds with respect to the total weight of the(incorporated) glycol compounds of the polyester resin component, inparticular 2,2,4,4-tetraalkylcyclobutane-1,3-diol and/or2,2,4,4-tetramethyl-1,3-cyclobutanediol;

-   -   (iii) an acrylic resin;    -   (iv) a fluorine containing polymer, in particular a hydroxyl        functional fluorine polymer;    -   (v) a polyurethane resin.

Polyester resin (components) comprising (incorporated) isophthalic acidmay be in particular advantageous for providing wheatering resistance.The cycloaliphatic glycol compound may be configured according toembodiments disclosed herein. As will be understood by those skilled inthe art and generally herein, a resin or polymer or an oligomerspecified as comprising or containing or consisting of monomers ormonomer groups means that the resin or polymer or oligomer hasincorporated the monomers or monomer groups.

According to a further embodiment, an Erichsen depth of at least 1 mm,in particular at least 2 mm, in particular at least 3 mm according tothe EN ISO 1520 is reached after curing the coating and if the coatinghas formed a layer thickness below 10 μm. According to an embodiment thecured coating material resists at least 5 acetone double rubs, inparticular at least 10 acetone double rubs, in particular at least 20acetone double rubs. According to a further embodiment the coatingmaterial is curable at least partly only by heat and/or by radiation.

According to an embodiment, the coating material has an absolute valueof chargeability of at least 5 μC/g, in particular of at least 10 μC/gand further in particular of at least 20 μC/g. According to a furtherembodiment the coating material exhibits an activation time of 1 to 15min, in particular 2 to 10 min tested in a standard Epping q/mequipment. According to an embodiment, the test is performed with a softblow.

According to an embodiment, the at least one crosslinking material ischosen from epoxy/glycidyl-group-containing materials, includingepoxy-resins and Triglycidylisocyanurate, hydroxyalkylamide (e.g. socalled primids) hardeners, isocyanate hardeners and/or double bondcontaining compounds with a thermal radical initiator system. Accordingto an embodiment, the coating material is a pure epoxy system (withregard to its resin/crosslinking material). According to a furtherembodiment, the epoxy material is used as a hardener for polyester.According to another embodiment, the resin is made out of at least onepolyester resin component and at least one epoxy resin component. Inthis case epoxy resin is a kind of hardener (crosslinking material) forpolyester resin. According to an embodiment, epoxy resin is in a lowerconcentration than polyester resin. However, in literature there is adiscussion that there is no more clear boundary as to when a resin iscalled a crosslinking material (also referred to as crosslinker) or aresin. Generally, according to an embodiment, a curing agent can also bea resin and also the same resin can be a crosslinking material if thechemistry allows crosslinking, like for example in epoxy systems.

According to an embodiment, resins comprising different resin components(e.g. epoxy/polyester) are called hybrid systems.

According to an embodiment, the coating material comprises a chargecontrol agent (CCA) in an amount, with respect to the entire coatingmaterial, of at least 0.5 w-%, in particular higher than 1 w-%, and inparticular higher than 1.5 w-%.

According to an embodiment, the CCA includes a zinc compound, inparticular a Zinc Salicylic compound, and in particular in aconcentration of higher than 90 w-% based on the overall amount of CCA.

According to an embodiment, the cross linking agent is contained in anamount between 0.3 and 1.7, in particular between 0.7 and 1.3 and inparticular between 0.9 to 1.1 of the molar ratio sufficient to cure theresin.

According to an embodiment, the resin comprises a polyester with anOH-value and/or COOH-value of at least 10 mg/g KOH determined viatitration and has an average molecular weight Mn between 500 and 10.000g/mol determined via gel permeation chromatography (GPC) and polystyrenestandards. According to a further embodiment, the polyester contains,with respect to the overall amount of incorporated acid monomers-groups,at least 5 w-% isophtalic acid, in particular at least 25 w-% inparticular at least 50 w-%, further in particular at least 85 w-% (ofisophtalic acid). According to an embodiment, the coating material is acurable system which has a stability of at least one year Floridaaccording to GSB and/or Qualicoat standards for architectural coatings.

According to a further embodiment, the coating material comprises withrespect to the entire amount of coating material less than 1 w-% ofleveling/flow additive, in particular organic levelling/flow additive,even more preferably less than 0.5 w-%, in particular less than 0.4 w-%and most preferably less than 0.1 w-%. As known in the art, flow andlevelling additives are chemical compounds that increase a coating'smobility after application, thus enabling the process of levelling (seee.g. 2010 Additives Handbook, Dr. Darlene Brezinski, Dr. Joseph V.Koleske, and Robert Springate, Jun. 4, 2010).

The leveling/flow additives mentioned above and below, which mainlyinfluence the surface tension of the coating material and hence improvethe (viscous) flow behaviour of the coating layer (and hence may also bereferred to as film flow or film leveling additives) have to bedistinguished from inorganic leveling or flow additive (herein alsoreferred to as powder leveling/flow additive) which is added to thesurface of the individual particles of the coating material, typicallydone by a dry blending and/or a bonding process, to alter the flowand/or charging properties of the individual powder particles.

According to a further embodiment, the coating material comprises, withrespect to the entire amount of coating material, less than 10 w-%,preferably less than 5 w-% and most preferably less than 1 w-% inorganicmaterial. In this regard, it is noted that if an inorganic material isused as a pigment, the amount may be higher. For example, according toan embodiment titanium dioxide may be included in an amount as specifiedif used as inorganic material, in particular as inorganic powderleveling additive or as powder flow additive. However, if titaniumdioxide is used as a pigment, the amount may be higher, in particulardepending on the desired appearance.

According to an embodiment, the coating material contains at least oneacrylic resin with epoxy equivalent weight of 100-2000 g/Eq, inparticular 200-1000 g/Eq, in particular 400-600 g/Eq.

According to a further embodiment, the resin of the coating materialcontains at least one polyester resin with an OH-value of at least 10mg/g KOH, in particular at least 80 mg/g KOH and further in particularat least 250 mg/g KOH. According to a further embodiment, the curingagent comprises an isocyanate hardener with a NCO-content of at least 5w-% to 30 w-% with respect to the overall amount of isocyanate hardener,in particular of at least 8-20 w-% and further in particular of at least12 w-%-15 w-% (with respect to the overall amount of isocyanatehardener). According to a further embodiment, the isocyanate hardener isblocked.

According to an embodiment, the coating material comprises an inorganicsurface additive. According to a further embodiment, the inorganicsurface additive comprises in particular one or more of inorganic oxidesof silicon and/or titanium, in particular with a particle size between 1nm and 100 nm, further in particular between 5 nm and 70 nm.

According to an embodiment, the coating material comprises two or moredifferent inorganic oxides with a ratio of the average particle diameterbetween 2 to 10, preferably 5 to 7. According to an embodiment,providing different inorganic oxides (e.g. of the same material, e.g.titanium (di)oxide or silicon (di)oxide) which have a particle sizedistribution in the specified range may improve charging capabilities ofthe coating material. This may be of advantage in an electrostaticprinting process (e.g electrophotographic printing process) (one exampleof a NIP process).

As commonly known an electrostatic printer is a type of printer in whichthe image is first written as a pattern of electrostatic charge, and isthen made visible by bringing the pattern into contact with particles ofpigment that carry a charge of opposite polarity. The pigment is onlyattracted to the charge pattern and is subsequently fused or bonded to atarget surface.

As further commonly known an electrophotographic printer is a type ofprinter in which the required image is written by a beam of light onto aphotoconductor (e.g. a photoconductive drum or band) that has a uniformelectric charge over its surface. The action of the beam of lightproduces a charge pattern on the photoconductor, which is then developedby applying particles of pigment that are attracted to the image but arerepelled by the background. The image is then transferred to the targetsurface by pressing the target surface against the photoconductor andapplying an electric field. The particles of pigment (also referred toas toner) is fixed to the target surface, e.g. by heat and/or pressureor by passing through a solvent vapor bath.

An electrophotographic printer can yield good print quality. It formsits image as a fine matrix of dots and is therefore capable of producinggraphics and a wide variety of typestyles. The most common example of anelectrophotographic printer is the laser printer.

According to an embodiment, the coating material comprises a compoundwhich includes chemical bonds which reversibly can be opened at anopening temperature between 50 and 200° C., preferably 75 and 150° C.and reversibly can be closed again below the opening temperature. Thismay allow the coating material to provide self-healing effects.

According to an embodiment, the coating material exhibits a minimumviscosity, when being heated from room temperature with a heating rateof 5 Kelvin per minute up to 180° C., 200° C. or 220° C. and/or to atemperature where curing of the coating material occurs, wherein theminimum viscosity is in a range between 3 Pascal seconds to 20000 Pascalseconds, in particular in a range between 50 Pascal seconds and 10000Pascal seconds and further in particular in a range between 250 Pascalseconds and 7000 Pascal seconds. According to an embodiment, the minimumof the viscosity is a local minimum of the viscosity with respect totemperature. According to an embodiment, the coating material is heatedwith a heating rate of 5 Kelvin per minute to an upper temperature whichis sufficiently high such that the viscosity over temperature (in otherwords the temperature dependent viscosity) shows a local minimum.According to an embodiment, the viscosity is determined with aconventional rheometer as it is known in the art.

According to an embodiment, the coating material exhibits a pill flowlength below 350 mm at a potential curing temperature which may be usedto cure the coating material, and wherein the pill flow length isdetermined by the following method:

-   -   (i) pressing an amount of 0.75 gram of the coating material into        a cylindrical pill with a diameter of 13 mm at a force of 20        kilo Newton, 20 kN, for at least 5 seconds;    -   (ii) putting the pill of coating material on a metal sheet at        room temperature;    -   (iii) putting the metal sheet with the pill into a furnace        preheated to the potential curing temperature and tempering the        pill on the metal sheet in a horizontal position for half a        minute if the resin includes an acrylic resin component and for        one minute if the resin does not include an acrylic resin        component;    -   (iv) tilting the metal sheet to a flowing down angle of 65° and        maintaining the metal sheet in this position for 10 minutes at        the potential curing temperature;    -   (v) removing the metal sheet from the furnace, cooling down the        metal sheet and the coating material in the horizontal position,        measuring a maximum length of the pill on the metal sheet and        taking this maximum length as the pill flow length.

According to an embodiment, the coating material is a thermosettingcoating material. According to a further embodiment, the thermosettingcoating material comprises a curable polyester resin (also referred toas polyester resin component), containing 1 to 100 wt-% ofcycloaliphatic glycol compound with respect to the total weight of the(incorporated) glycol compounds of the curable polyester resin. Such acurable polyester resin can be used as component of the thermosettingcoating material (e.g. a thermosetting powder composition). Thecycloaliphatic glycol components can comprise in particular2,2,4,4-tetraalkylcyclobutane-1,3-diol (TACD), wherein each alkylsubstituent can comprise up to 10 carbon atoms and wherein the alkylsubstituents can be linear, branched or a mixture thereof and whereinthe diols can be either cis- or trans-diols. The curable polyester cancomprise any possible mixture of isomers of TACD.

According to an embodiment the cycloaliphatic compound comprises orconsists of 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD).

According to another embodiment the coating material comprises a mixturecontaining 1 to 99 wt-% of TMCD isomer(s) and 99 to 1 wt-% ofcycloaliphatic 1,4-cyclohexanedimethanol isomer(s) (CHDM) with respectto the total weight of the cycloaliphatic glycol compounds of thecurable polyester. According to an embodiment, the mixture consists ofthe TMCD isomers and the CHDM isomers.

According to another embodiment, the curable polyester resin comprisespolyol compounds, other than the cycloaliphatic glycol compounds,containing at least 1 hydroxyl group (e.g. at least 2 hydroxyl groups)and representing at least 1 wt-% with respect to the total weight of all(incorporated) polyol compounds of the curable polyester.

The aforementioned curable (thermosetting) polyester resins areparticularly useful for outdoor applications because at least one of thefollowing properties can be achieved after curing: good chemicalresistance, good hydrolytic stability, good weathering stability, highheat resistance, high scratch resistance, high impact strength,toughness, high ductility, good photooxidative stability, transparencyand flexibility.

According to an aspect of the herein disclosed subject matter, a use ofa coating material is provided, in particular a use of a coatingmaterial according to one or more embodiments of the herein disclosedsubject matter is provided.

According to an embodiment, there is provided a use of a coatingmaterial for applying a coating layer to a target surface by means of aNIP device.

In accordance with an embodiment, there is provided a use of a developerfor generating from the coating material the coating layer according toembodiments disclosed herein.

According to an embodiment, the coating material is used for applying alayer of the coating material to a target surface, in particular bymeans of a NIP device, in particular to a target surface of a transferelement or a target surface of a substrate.

In a special embodiment the coating material can be applied (printed) toa transfer element and then the printed coating material layer can betransfered to a final substrate. Any technology known for such transfersare within the scope of the herein disclosed subject matter. For examplethe use of transfer sheets, decals, water transfer printing or waterslide printing can be used. A decal may be a plastic, cloth, paper orceramic substrate that has printed on it a pattern or image that can bemoved to another surface upon contact.

According to a further embodiment, the coating material is used forapplying different layers of the coating material to the target surfaceof the substrate, wherein in particular the substrate is a precoatedsubstrate which comprises a pre-coating, in particular a pre-powdercoating.

According to a further embodiment, a use of a coating material accordingto one or more embodiments is provided for applying a layer of thecoating material to a target surface, in particular by means of a NIPdevice, in particular to a target surface of a transfer element or atarget surface of a substrate; in particular for applying differentlayers of the coating material to the target surface of the substrate,wherein in particular the substrate is a precoated substrate whichcomprises a pre-coating, in particular a pre-powder coating.

According to an embodiment, the coating material comprises the sameresin, in particular the same type of resin or the same resin system,and the same hardening system, in particular the same curing agent, likethe pre-coating (e.g. an undercoat or basecoat) on the substrate.Herein, the type of resin refers to the chemical system of a resin or aresin component. An example of a type of resin is for example apolyurethane type. According to a further embodiment, the coatingmaterial comprises the same resin system as the pre-coating on thesubstrate. The same resin system may be the polyurethane system.

According to an embodiment, at least one coating material (each of whichis configured according to one or more embodiments of the hereindisclosed subject matter) is used for printing at least one layer, inparticular at least two layers (of the same coating material or ofdifferent coating materials) on top of each other, in particular in twodistinct printing processes, e.g. by two different printing units or intwo different runs of the same printing unit. According to anembodiment, each layer comprises functional groups that can react withfunctional groups of the previous layer, e.g. when heated. According toan embodiment, the functional groups are one or more of COOH, OH, NCOand Epoxy.

According to an aspect of the herein disclosed subject matter, a methodis provided.

According to an embodiment, the method comprises applying a coatinglayer (e.g. at least one coating layer) generated from (e.g. beingformed from) a coating material (e.g. at least one coating material)according to one or more embodiments of the herein disclosed subjectmatter to a target surface, in particular by means of a NIP device.

According to an embodiment, the target surface is a surface of atransfer element which is used to transfer the coating layer to asubstrate.

According to a further embodiment, the target surface is a surface of asubstrate.

According to an embodiment, the method comprises applying a top coat tothe coating layer, in particular if the coating layer is located on thesubstrate.

According to an embodiment, the topcoat is a clear top coat. Accordingto a further embodiment, the topcoat is provided as a printed layer oras a coated layer. In particular, the topcoat may be provided as a(further) coating layer according to embodiments of the herein disclosedsubject matter or by conventional processes such as powder coating. Inparticular the coating layer comprises at least one of UV-absorber oranti-yellowing agent. According to an embodiment, the top coat is acontinuous layer, e.g. a layer which covers the entire surface. Inanother embodiment the top coat is a structured top coat which covers adefined area (e.g. in the shape of a character).

According to an embodiment, the method comprises curing the top-coatseparately from the coating layer, wherein in particular the coatinglayer comprises free functional groups for the connection of the coatinglayer and the topcoat.

According to a further embodiment, the method comprises curing togetherthe top-coat and the coating layer, wherein in particular the coatingmaterial is a powdery coating material and the top coat is applied as apowdery top coat layer before the curing together of the coating layerand the top coat layer.

It is noted that any embodiment which refers to a powdery coatingmaterial shall be considered as also disclosing a respective embodimentwhich refers instead to a coating material which is provided in the formof a plurality of particles. In this sense, a powder shall be understoodas also disclosing, according to an embodiment, a plurality ofparticles.

According to an embodiment, the substrate is a precoated substrate whichcomprises a pre-coating, in particular a pre-powder coating. Accordingto a further embodiment, the coating material comprises the same resintype (e.g. polyesters, acrylics, fluorinepolymers, polyurethanes,epoxies) and the same hardening system as the pre-coating on thesubstrate. According to an embodiment, the coating material comprisesthe same resin and/or the same curing agent as the pre-coating on thesubstrate.

According to an embodiment, a layer thickness of the topcoat is at least10 μm, in particular at least 20 μm and further in particular at least40 μm.

According to an embodiment, the substrate is a glass substrate or aceramic substrate. In such a case, according to an embodiment the methodfurther comprises a pretreatment of the substrate with an adhesionpromoter and/or addition promoter, wherein the adhesion promoter is inparticular pyrolytically deposited silicon dioxide, in particularpyrosil.

According to an embodiment, a reservoir, in particular a cartridge, fora NIP device, is provided, the reservoir comprising a coating materialaccording to one or more embodiments of the herein disclosed subjectmatter. According to an embodiment, a nonimpact printing deviceaccording to embodiments of the herein disclosed subject matter requires(in particular due to the thickness of a coating layer or a coatinglayer package as described herein) a relatively large amount of coatingmaterial. According to an embodiment, the reservoir is respectivelyadapted, e.g. regarding volume, geometry and/or structure adapted to thevolume, etc.

According to an embodiment, a developer is provided, in particular adeveloper for a two-component (2K) system comprising the coatingmaterial according to one or more embodiments and a carrier, inparticular a carrier for electrophotographic printing as describedherein or as known in the art.

According to another embodiment the carrier comprises non-magneticcarrier particles (soft carrier particles). According to anotherembodiment the carrier comprises magnetic carrier particles (hardcarrier particles).

According to an embodiment, the reservoir (e.g. the cartridge) is areservoir for a two-component (2K) system comprising the coatingmaterial according to one or more embodiments and a carrier, inparticular a carrier for electrophotographic printing as describedherein or as known in the art. In other words, the reservoir maycomprise the developer. In this sense, herein any reference to areservoir content may be considered as a reference to a developer.

According to an embodiment, the reservoir content (which includes inparticular the coating material and the carrier) comprises at least 4w-% of the coating material based on the overall weight of the reservoircontent, in particular at least 6 wt-%, further in particular at least 8w-%, further in particular at least 10 w-%, further in particular atleast 16 w-%, and further in particular at least 20 w-% of the coatingmaterial based on the overall weight of the reservoir content. Accordingto a further embodiment, the reservoir content comprises the coatingmaterial in a range between 4 w-% and 30 w-% based on the overall weightof the reservoir content. According to an embodiment, the reservoircontent comprises 10% or less of the coating material based on theoverall weight of the reservoir content. According to a furtherembodiment, the reservoir content consists of coating material andcarrier. In this case, an amount of 8 w-% of the coating materialcorresponds to an amount of 92 w-% of the carrier. Hence, contrary toconventional toner systems, a cartridge according to embodiments of theherein disclosed subject matter may comprise a relatively large amountof coating material (i.e. of the material that is printed). According toan embodiment, the carrier in the reservoir may be reused (e.g. if thereservoir is a built-in reservoir) or may be exchangeable (e.g. with anexchangeable cartridge into which the carrier is confined).

According to an embodiment, a NIP device is provided, the NIP devicecomprising a coating material according to one or more embodiments ofthe herein disclosed subject matter.

According to an embodiment, a transfer element is provided, the transferelement comprising a coating layer generated from a coating materialaccording to embodiments of the herein disclosed subject matter.

According to an embodiment, a substrate is provided, in particular apre-coated substrate, the substrate comprising a coating layer generatedfrom a coating material according to embodiments of the herein disclosedsubject matter.

According to an embodiment, a coating layer application device isprovided, the coating layer application device being configured forreceiving a transfer element comprising a coating layer generated from acoating material according to one or more embodiments of the hereindisclosed subject matter. According to an embodiment, the coating layerapplication device is further configured for applying the coating layerto a substrate.

In particular the formation of micro scale droplets can be avoided byone of more of the following:

In an embodiment the coating composition comprises auxiliary components,in particular solids comprising silicon compounds and/or titaniumcompounds and derivatives thereof. It has been surprisingly found by theinventors that such auxiliary components may act as separating agentswhich may reduce the undesired adhesion effects of micro-scale droplets,which are responsible for the distortion of the printed image. In aparticular embodiment, the particles of the auxiliary components, inparticular the silicon and/or titanium compounds have an averagenanoscale diameter, more in particular a mean diameter of about 5 nm toabout 70 nm (nanometer). Further ways for avoiding the formation ofmicro-scale droplets can be taken from the described examples which maybe generalized correspondingly.

With respect to the described auxiliary components in particular in thecase of the silicon compounds it was found that such components areparticularly effective in conjunction with charge control agents inorder to provide a suitably stable and equally distributed charge of theparticles, being stable over several hours. Summarizing, it is inparticular the combination of the charge control agent with at least onefurther auxiliary component, in particular silicon compounds and/orderivatives thereof, which allow for a high quality non-impact printingprocess.

In an embodiment the coating composition comprises a polymer withsufficient amount of free hydroxyl groups or free reactive groups likeCOOH, OH, epoxy and/or NCO. Such a polymer with a plurality of freefunctional groups (e.g. free hydroxyl groups) allows for suitableadherence between the various layers built up upon each other. Thisbecomes in particular striking, when the coating according to theapplication is used for repairing or refreshing surfaces which have beencoated by conventional coating methods. The free functional groups (e.g.the free hydroxyl groups) then allow for suitable adherence of thefreshly added coating to the coating composition already present.

In an embodiment, the method for providing the coating by non-impactprinting comprises the step of pre-curing the coating material. Such apre-curing step may be performed by applying one or more of thefollowing: heat, pressure, electron beam and electromagnetic radiation,in particular UV radiation.

The step of pre-curing the coating material may be such that it leavesat least some of the functional groups, i.e. reactive groups, free, i.e.unreacted. Since such free reactive groups are then available for areaction with functional groups on the surface of the lower layer, thepre-cured coating material can strongly and reliably bind to the lowercoating layer which allows for the successive build-up of a plurality ofdifferent layers, which finally form a coherent and stable structure. Apre-curing step of the coating material is therefore in particularadvantageous for successively applying a plurality of layers above eachother. In a particular embodiment, the pre-curing step is such that itenables the reaction of functional groups, in particular of the reactivecrosslinkable functional groups, with each other, under the premise thatat least 1%, in particular at least 5%, more in particular at least 10%,more in particular at least 30% of the reactive functional groups, inparticular of the reactive crosslinkable functional groups, are leftunreacted.

Due to the described advantageous adherence to a plurality of differenttypes of surfaces and different surface shapes, the describedcomposition as well as the described method for applying such acomposition can advantageously be used for the renewal of an alreadypowder coated surface. For instance a coated surface which over thetime, for example due to harsh weather conditions or other mechanicalstress, has lost at least partially some of its desired properties, forinstance color intensity, may be restored by (selectively) applying thecoating as described in the present application.

Embodiments of the herein disclosed subject matter preferably use zincsalicylic compounds as the so-called CCA in a concentration of at least2% (based on overall weight). Experiments show that these CCAs affectthe charging properties of the particles of the coating material (alsoreferred to as toner particles) not as expected. No linear correlationof the charging capability with increasing amount of CCA was observed.Still the CCA may be a highly important component of the coatingmaterial particles because examples show that it may be crucial toobtain the desired color density (optical impression), while notinfluencing the color stability (UV exposure). Zinc salicylic compoundscan be used to obtain the desired color density for all colors (CMYK,white) necessary for printing a high-resolution color image. So onemight call the zinc salicylic compounds a color density agent ratherthan CCAs in the case of the herein disclosed coating materialparticles.

The toners according to embodiments of the herein disclosed subjectmatter are suitable for high resolution and quality printing, which is amajor novelty regarding powder coating based toner particles.Furthermore, according to an embodiment coating materials according tothe herein disclosed subject matter are produced in a single procedure(single extrusion of the base materials (e.g. resin and furthercomponents of coating material) and subsequent milling) and are not madeby re-compounding conventional powder coatings with additives and thelike. Consequently, no double extrusion and additional steps arenecessary to produce the coating material resulting in lower costs,environmental advantages, decreased energy requirements, no undesiredpre-reactions due to elevated temperatures or shear forces.

According to an embodiment, the coating materials differ fromconventional toners in particular regarding the particle sizedistribution and the different particle composition and structure.

Conventional, chemically produced toners for printing may comprise acore-shell structure often consisting of two different resins and areoften produced by emulsion/aggregation processes. Additives, pigments,the CCA, waxes and the like are often located in the core of theseparticles. Overall, the core-shell structure results in an inhomogeneoustoner particle.

In contrast, according to an embodiment of the herein disclosed subjectmatter the coating material particles are homogeneous. In particular,according to an embodiment the coating material particles arehomogeneous in a sense that the coating material particles are free froman internal structure (of different composition) with dimensionscomparable to the particle size (e.g. structures with a dimensionsbetween 0.6 to 1 times the particle size or between 0.8 to 1 times theparticle size) is defined as homogeneity regarding the composition pervolume unit. According to a further embodiment homogeneity is defined asthe average number of particles or repeat units (for resins) of eachtoner component per volume element of the toner particle. It is notedthat the term homogeneous does not necessarily mean homogeneous in thesense of homogeneous mixtures since usually distinguishable phases arepresent. Another suitable definition of homogeneity may be the averagemass per volume element of the toner particle, resulting in a ratheruniform density distribution for the coating material particles, whereasin contrast conventional chemically produced core-shell toner particlesshould show a significant density gradient at the core-shell border.

The particle size distribution of the charge control agent according toembodiments of the herein disclosed subject matter is believed to leadto better homogeneity of the coating material particles and thereby theenhancement of color density.

Embodiments of the herein disclosed subject matter make possible theprinting of high-resolution and quality images with curable coatingmaterial.

According to an embodiment, a NIP technique uses a soft magnetic brush(i.e. initially non magnetic particles (soft carrier particles).

According to an embodiment in the preparation of the coating materialthe processing of the constituents of the coating material is conductedso as to prevent pre-reaction of the coating material. This may limitthe processing time in an extruder so that the dispersion may not be ashigh as in a conventional thermoplastic toner (which does not cure).Without being bound to theory it is believed that this may be a reasonfor the positive effect provided by relatively high concentrations ofCCA. However, according to another embodiment, the coating material maybe free from CCA, in particular with transparent coating materials.

Chapter 2

According to an embodiment, the coating material is configured forgenerating a coating layer by NIP, the coating material being providedin the form of a plurality of particles. According to an embodiment, thecoating material comprises resin. According to an embodiment, the resincomprises a curable resin component. According to a further embodiment,the resin further comprises an amorphous resin portion. According to afurther embodiment, the resin component is at least partially thermallycurable, in particular curable by a crosslinking agent able to reactwith functional groups of the resin component. According to a furtherembodiment, the coating material comprises a charge control agent.

According to an embodiment, the content of the charge control agent isless than 20% based on the overall weight of coating material. Accordingto a further embodiment, the content of the charge control agent is in arange between 0.1 w-% to 10 w-%, in particular 0.2 w-% to 5 w-%, furtherin particular 0.5 w-% to 3 w-%, based on the overall weight of thecoating material. According to a further embodiment the content ofcharge control agent is at least 0.1 w-% based on the overall coatingmaterial, in particular at least 1 w-% and further in particular atleast 2 w-% based on the overall weight of coating material.

According to an embodiment, a glass transition temperature of theuncured coating material is higher than 45° C. and lower than 90° C.,and is preferably in a range between 50° C. and 70° C.

According to an embodiment, the charge control agent includes one ormore of the following:

-   -   a modified inorganic polymeric compound,    -   an organic metal complex (e.g. azo-metal Cr3+),    -   a boro-potassium salt, in particular potassium borobisbenzilate    -   a zinc salicylic compound, in particular Zinc Salicylate    -   an oxy carboxylic acid zinc complex    -   a metal chelate compound, in particular of alkylsalicylic acid        or hydroxynaphthoic acid,    -   a quaternary ammonium salt,    -   an oxide of a metal alkyl,    -   a salicylic acid metal complexe,    -   a calixarene compound,    -   an organic boron compound    -   an Azine or Azine compounds    -   an phenol compound, in particular phenol sulfides.

According to an embodiment, the amount of the amorphous resin portion islarger than 5 w-%, in particular larger than 20 w-% and further inparticular larger than 50 w-%, based on the overall weight of thecoating material.

According to an embodiment, the coating material comprises a salicyliccompound, in particular a zinc salicylic compound.

According to a further embodiment, the resin comprises one or more ofthe following:

-   -   (i) a polyester resin component comprising in particular        terephtalic acid and/or isophtalic acid;    -   (ii) a di- or polyisocyanate;    -   (iii) an acrylic resin, e.g. methacrylic resin;    -   (iv) a fluorine containing polymer preferably a hydroxyl        functional fluorine polymer    -   (v) a polyester resin component comprising a cycloaliphatic        glycol compound;    -   (vi) a polyurethane resin.

According to an embodiment (i) to (vi) each may be referred to as a typeof resin.

According to an embodiment, the polyester is a polyester which istransferable at least partly to a urethane material during curing.

According to an embodiment, a particle size distribution of the chargecontrol agent exhibits a d10 of between 0.5 and 5 μm, and/or a d90 ofbetween 5 and 50 μm. According to a further embodiment, the particlesize distribution of the charge control agent exhibits a d10 of between0.5 μm and 3 μm and/or a d90 of between 5 and 25 μm. According to afurther embodiment, the particle size distribution of the charge controlagent exhibits a d10 below 2 μm and/or a d90 below 10 μm. Herein and asis generally known, a specific value for dx (in the above examples x=10or x=90) indicates that an amount x of the particles is smaller than thespecified size.

According to an embodiment, wherein coating material is curable suchthat a cured coating layer made from the coating material exhibits oneor more of the following properties:

-   -   a remaining gloss after 300 hours of UV exposure according to        GSB international AL631-PartVll-segment 20.1 Kurzbewitterung        UV-B (313) is at least 50%, in particular at least 85%;    -   a remaining gloss after 600 hours of UV exposure according to        the test procedure of GSB international AL631-PartVll-segment        20.1 Kurzbewitterung UV-B (313) is at least 50%, in particular        at least 85%;    -   a remaining gloss after 1000 hours of Xenon exposure according        to EN ISO 16474-2 determined according to ISO 2813, is at least        50%, in particular at least 85%;    -   and in particular wherein the coating material comprises a        polyester resin and/or a di- or polyisocyanate compound and/or        urethane resin and/or an acrylate resin and/or Fluor-polymer        resin.

In particular the polyisocyanate compound may react to polyurethane withOH groups, e.g. of an OH group polyester.

According to an embodiment, the charge control agent is transparent oris at least partially transparent. According to a further embodiment,the charge control agent is black. According to a further embodiment,the charge control agent has a gray color, in particular a light graycolor or a white color.

According to an embodiment, the coating material is configured so as toallow a resolution of the NIP of more than 2 l/mm, in particular morethan 5 l/mm and further in particular more than 10 l/mm.

According to an embodiment, the coating material is configured forproviding a coating layer by the NIP with a thickness of at least 40 μm,in particular of at least 20 μm and further in particular of at least 10μm. According to a further embodiment, an optically perceptible contrast(resulting e.g. from different coating material (e.g. of differentcolors)) in the coating layer extends continuously from a top surface ofthe coating layer to a bottom surface of the coating layer.

According to an embodiment, the coating material is further configuredto allow an improvement of an adhesion of a coating layer made from thecoating material on a substrate by application of pressure.

According to a further embodiment, the coating material furthercomprises at least one solid carrier configured for carrying the coatingmaterial in the NIP.

According to an embodiment, there is provided a use of a coatingmaterial according to embodiments of the herein disclosed subject matterfor NIP of a coating layer. According to an embodiment, the coatingmaterial is used for direct NIP of the coating layer onto a substrate,in particular a precoated substrate.

According to a further embodiment, the coating material is used forindirect NIP of the coating layer onto a transfer element which isconfigured for transferring the coating layer to a substrate.

According to an embodiment, the processing device is configured forprocessing a coating material according to embodiments of the hereindisclosed subject matter, the processing device comprising in particularat least one of: a NIP device configured for printing the coatingmaterial to thereby generate a coating layer; and/or a pretreatmentdevice configured for treating the coating layer before application ofthe coating layer to a substrate; a coating layer application device forapplying the coating layer, printed onto a transfer element, from thetransfer element to the substrate; a curing device for curing thecoating layer applied to the substrate; in particular wherein one ormore of the NIP device, the pretreatment device, the coating layerapplication device, and the curing device are located at the samelocation and/or one or more of the NIP device, the pretreatment device,the coating layer application device, and the curing device are locatedin different locations.

According to embodiments of the herein disclosed subject matter, theprocessing device may include any feature disclosed herein with regardto one or more of the following devices: of the NIP device, thepretreatment device, the coating layer application device, and thecuring device; in particular without requiring the respective device assuch.

According to an embodiment, the method of processing a coating materialaccording to embodiments of the herein disclosed subject matter includesin particular at least one of:

-   -   printing the coating material to thereby generate a coating        layer;    -   treating the coating layer before application of the coating        layer to a substrate;    -   applying the coating layer, printed onto a transfer element,        from the transfer element to the substrate;    -   curing the coating layer applied to the substrate.

According to an embodiment, the reservoir, in particular a cartridge,which is in particular provided and/or configured for a NIP device (301,400), comprises a coating material according to embodiments of theherein disclosed subject matter.

According to an embodiment, the transfer element comprises a coatinglayer generated from a coating material according to embodiments of theherein disclosed subject matter.

According to an embodiment, the substrate, in particular a pre-coatedsubstrate, comprises a coating layer generated from a coating materialaccording to embodiments of the herein disclosed subject matter.According to a further embodiment, the substrate and/or the pre-coatingcomprises free functional groups able to react with the applied coatinglayer. According to an embodiment, the coating layer has a thickness ofat least 10 μm, in particular a thickness of at least 20 μm and furtherin particular a thickness of at least 40 μm. According to a furtherembodiment, the coating layer represents an image and wherein aresolution of the image is at least 100 DPI, in particular at least 200DPI and further in particular at least 300 DPI.

According to an embodiment, the coating layer (in particular on thesubstrate and/or representing (showing) the image) is cured.

In an embodiment, the charge control agent has values of D10 in a rangeof 0.5 μm to 3 μm, D50 of 2 μm to 8 μm, and D97 of 8 to 12 μm. In a moreparticular embodiment, the charge control agent has values of D10 ofabout 2 μm, D50 of about 5 μm and D97 of about 10 μm. In an even moreparticular embodiment, the charge control agent has values of D10 in arange of 0.5 μm to 3 μm, D50 of 2 μm to 8 μm, and D97 of 8 to 12 μmwhile the charge control agent is present in an amount of at least 2w.-%, more preferably in an amount of 2 w.-% to 3 w.-%. In a moreparticular embodiment, the charge control agent has values of D10 ofabout 2 μm, D50 of about 5 μm and D97 of about 10 μm while the chargecontrol agent is present in an amount of at least 2 w.-%, morepreferably in an amount of 2 w.-% to 3 w.-%.

According to an embodiment, the coating material comprises one or moreflame retardants as known in the art. For example, according to anembodiment, the flame retardant is at least (but not limited to) one ofa mineral, an organohalogen compound and an organophosphorus compound.

Chapter 3

According to an embodiment, the coating layer application device isconfigured for applying a coating layer, which is located on a transferelement, to a substrate, the coating layer being formed from a coatingmaterial (in particular a coating material according to embodiments ofthe herein disclosed subject matter, further in particular athermosetting coating material), the coating layer being in particularcurable, the coating layer comprising in particular an amorphousmaterial.

The coating layer application device comprises: a heating device (or, inanother embodiment, a (first) energy transfer device) being configured(or used) so as to (i) maintain the temperature of the coating layerwithin a temperature range (hereinafter also referred to as firsttemperature range) before removal of the transfer element from thecoating layer, wherein within the first temperature range the uncuredcoating material is in its supercooled liquid state and/or in its glassystate; and/or (ii) partially cure the coating layer during a contact ofthe coating layer and the substrate and before removal of the transferelement from the coating layer, in particular by increasing thetemperature of the coating layer to a temperature at or above a curingtemperature of the coating layer.

According to an embodiment, maintaining the temperature of the coatinglayer within a temperature range can be performed with any suitablemeans (heating the coating layer directly, heating the coating layerindirectly (e.g. by heating the substrate and/or the transfer element).According to an embodiment, the heating device (or the first energytransfer device) may be located for heating the substrate before acontact of the substrate with the coating layer. According to a furtherembodiment, the heating device (or the first energy transfer device) maybe located for heating the transfer element before a contact of thesubstrate with the coating layer.

According to an embodiment, the coating layer comprises a crystallinephase or can be at least partially brought into the crystalline phase,wherein the crystalline phase defines a melt temperature and the firsttemperature range is below the melt temperature. According to a furtherembodiment, the coating material exhibits one or more of the followingfeatures: the coating material is free from crystalline resin; thecoating material exhibits no first order phase transition due tomelting, in particular at least not within the first temperature range.

According to a further embodiment, the coating layer application devicefurther comprises: a printing device being configured for applying thecoating material to the transfer element by printing to thereby form thecoating layer.

According to an embodiment, the printing device is a NIP device, e.g. anelectrostatic printing device such as a laser printing device or a LEDprinting device.

According to a further embodiment, the printing device is configured forapplying the coating material to the transfer element with a thicknessof at least 1 micrometer (1 μm), in particular at least 2 μm, inparticular at least 5 μm, in particular at least 10 μm, and further inparticular with a thickness of at least 20 μm, for example with athickness of at least 40 μm.

According to an embodiment, the printing device is configured forapplying the coating material as a pattern to the transfer element tothereby form the coating layer as a patterned coating layer exhibitingthe pattern.

According to an embodiment, the patterned coating layer exhibiting atleast one of the following features: (i) the patterned coating layerexhibits a haptic effect; (ii) the patterned coating layer defines asurface structure, wherein the surface structure is defined by athickness variation of the patterned coating layer; (iii) the pattern isa first pattern which combines with a second pattern to a combinedpattern, in particular wherein the second pattern is formed from thesame coating material or from a different coating material; inparticular wherein the first pattern and the second pattern are locatedin a common layer plane; in particular wherein the first patterncomprises at least one void and wherein the second pattern at leastpartially fills the at least one void.

According to a further embodiment, the pattern (e.g. an image) extendsentirely through the coating layer transverse to a layer plane of thecoating layer.

According to a further embodiment, the printing device is configured forapplying the coating material to the transfer element with a resolutionof more than 2 l/mm, in particular with a resolution of more than 5l/mm, e.g. with a resolution of more than 10 l/mm.

According to an embodiment an energy transfer device (e.g. second energytransfer device) is provided, the energy transfer device beingconfigured (or used) for transferring energy, in particular heat and/ora radiation like UV radiation and/or an electron beam, into the coatinglayer on the transfer element, in particular before the contact of thecoating layer and the substrate (to which the coating is applied).According to an embodiment the energy transfer device is configured fortransferring energy, in particular heat and/or a radiation like UVradiation and/or an electron beam, into the coating layer on thetransfer element during and/or after the contact of the coating layerand the substrate. According to an embodiment, the energy transferdevice is configured for transferring the energy to the coating layer soas to partially cure the coating layer on the transfer element and/or toinduce viscous flow in the coating layer on the transfer element).According to an embodiment, the energy transfer device is configured forproviding energy in the form of at least one of heat, radiation,pressure, in particular to thereby induce the viscous flow. According toan embodiment, the coating layer application device (or, in anotherembodiment, the printing device) comprises the energy transfer device.

According to an embodiment, the energy transfer device (e.g. the firstenergy transfer device and/or the second energy transfer device)comprises a heatable roller. According to a further embodiment, anenergy transfer device (e.g. the first energy transfer device and/or thesecond energy transfer device) comprises a heating device for heatingthe transfer element and/or for heating the substrate. For example,according to an embodiment, the transfer device is a heatable transferdevice that includes a heating device.

According to an embodiment, the partial curing of the coating layer isperformed by heating the coating layer (e.g. with an energy transferdevice or heating device according to one or more embodiments of theherein disclosed subject matter) with a first heating rate to atemperature above the curing temperature and subsequent cooling (intothe supercooled liquid state or into the glassy state, e.g. to roomtemperature) with a second heating rate (negative heating rate=coolingrate). According to an embodiment the first heating rate and the secondheating rate are higher than 10 K/min, in particular higher than 20K/min, further in particular higher than 50 K/min and further inparticular higher than 100 K/min. According to an embodiment the firstheating rate and the second heating rate are in a range higher between10 K/min and 100 K/min.

It should be noted that partial curing means curing to a curing degreewhich is less than full curing. However, the main aspect is that onlypartial curing happens. Such partial curing can be defined in that waythat after this partial curing still some reaction heat is given orconsumed depending on the type of reaction (endotherm or exotherm orcombinations thereof). Also a shift of higher than 1-2° C. of the Tgmeasured with DSC with a heating rate of 20 K/min of the coating(measured before and after (another) curing cycle) is a good indicationthat only partial curing has happened. Preferably based on the heatformation/consumption of the reaction a partial curing of below 80%,even more preferably below 50% is chosen.

According to an embodiment, a compaction device is provided thecompaction device being configured for compacting the coating layer onthe transfer element before the contact of the coating layer and thesubstrate. According to an embodiment, the coating layer applicationdevice (or, in another embodiment, the printing device) comprises thecompaction device.

According to an embodiment, the transfer element having the coatinglayer thereon is a separate part and e.g. a transfer element support isconfigured for receiving the transfer element having the coating layerthereon as a separate part. Further, according to an embodiment theprinting device is configured such that the transfer element isremovable from the printing device.

According to an embodiment, the method comprises: providing a transferelement having thereon a coating layer which comprises an amorphousmaterial and is curable, preferably at least partly curable by exposureto heat; bringing into contact the coating layer on the transfer elementand a substrate in order to apply the coating layer to the substrate.

According to an embodiment, the method comprises maintaining thetemperature of the coating layer within a first temperature range beforeremoval of the transfer element from the coating layer. According to anembodiment, within the first temperature range the uncured coatingmaterial is in its supercooled liquid state and/or in its glassy state.

According to a further embodiment, the method comprises partially curingthe coating layer during the contact of the coating layer and thesubstrate and before removal of the transfer element, in particular byincreasing the temperature of the coating layer to a temperature at orabove a curing temperature of the coating layer.

According to a further embodiment, wherein the coating layer comprises acrystalline phase or can be at least partially brought into thecrystalline phase, wherein the crystalline phase defines a melttemperature and the first temperature range is below the melttemperature; or wherein the coating material exhibits one or more of thefollowing features: the coating material is free from crystalline resin;the coating material exhibits no first order phase transition due tomelting, in particular at least not within the first temperature range.

According to a further embodiment, the method further comprises applyingthe coating material to the transfer element by printing (in particularby NIP) to thereby form the coating layer.

According to a further embodiment, the coating material is applied tothe transfer element with a thickness of at least 1 micrometer (1 μm),in particular at least 2 μm, in particular at least 5 μm, in particularat least 10 μm, and further in particular with a thickness of at least20 μm, for example with a thickness of at least 40 μm.

According to an embodiment, the coating material is applied as a patternto the transfer element to thereby form the coating layer as a patternedcoating layer exhibiting the pattern. According to an embodiment, thepatterned coating layer exhibits at least one of the following features:the patterned coating layer exhibits a haptic effect; the patternedcoating layer defines a surface structure, wherein the surface structureis defined by a thickness variation of the patterned coating layer; thepattern is a first pattern which combines with a second pattern to acombined pattern, in particular wherein the second pattern is formedfrom the same or a different coating material; in particular wherein thefirst pattern and the second pattern are located in a common layerplane; in particular wherein the first pattern comprises at least onevoid and wherein the second pattern at least partially fills the atleast one void.

According to an embodiment, the pattern (e.g. an image) extends entirelythrough the coating layer transverse to a layer plane of the coatinglayer.

According to an embodiment, the coating material is applied to thetransfer element with a resolution of more than 2 l/mm, in particularwith a resolution of more than 5 l/mm, e.g. with a resolution of morethan 10 l/mm.

According to an embodiment, the method comprises transferring energy, inparticular heat and/or a radiation like UV radiation and/or an electronbeam, into the coating layer on the transfer element before the contactof the coating layer and the substrate; in particular transferring theenergy to the coating layer so as to partially cure the coating layer onthe transfer element and/or to induce viscous flow in the coating layeron the transfer element, in particular wherein the energy is in the formof at least one of heat, radiation, pressure.

According to an embodiment, the coating layer on the transfer element iscompacted before the contact of the coating layer and the substrate(i.e. before contact of the coating layer and the substrate is made).For example, according to an embodiment the method comprises compactingthe coating layer on the transfer element before the contact of thecoating layer and the substrate.

According to an embodiment, the transfer element, having the coatinglayer thereon, is received as a separate part. For example, according toan embodiment the method comprises receiving the transfer element,having the coating layer thereon, as a separate part.

According to an embodiment, the computer program product comprises aprogram element, the program element being adapted for, when executed ona processor device, performing the method according to embodiments ofthe herein disclosed subject matter.

According to an embodiment, the NIP device comprises: a coating materialbeing curable and comprising an amorphous material; a printing unitbeing configured for applying the coating material to a transferelement, in particular to a target surface on the transfer element; andin particular an energy transfer device being configured fortransferring energy to the coating material on the transfer element.

According to an embodiment, the energy transfer device is configured fortransferring the energy to the coating material so as to partially curethe coating material of the coating layer on the transfer element and/orto induce viscous flow in the coating layer on the transfer element, inparticular wherein the energy is at least one of heat, radiation,pressure.

According to an embodiment, the energy transfer device is configured fortransferring the energy to the coating material before a contact of thecoating material and a substrate to which the coating material is to beapplied.

According to an embodiment, the transfer element comprises a coatinglayer, the coating layer being formed from a coating material, thecoating layer being curable and comprising an amorphous material.According to a further embodiment, the coating layer is transferable toa substrate and in particular comprises a charge control agent.According to a further embodiment, the transfer element is a standalonetransfer element (e.g. a separate part), e.g. a transfer element that isremovable from a processing device by which it is processed. Inparticular, in accordance with an embodiment, the (standalone) transferelement with the coating layer thereon is removable from the processingdevice. According to a further embodiment, the standalone transferelement is a transportable transfer element. In particular, inaccordance with an embodiment, the standalone transfer element with thecoating layer thereon is transportable. For example, according to anembodiment, the standalone transfer element is a transfer film, e.g. amicroperforated transfer film as described herein. Manufacture of astandalone transfer element comprising a coating layer allows separatemanufacture, storage, marketing and shipping of the standalone transferelement which comprises the coating layer. At the customer premises thecoating layer on the standalone transfer element may then be transferredonto a substrate, e.g. by a coating layer application device disclosedherein.

According to an embodiment, the coating material (e.g. on the transferelement) comprises a resin, wherein the resin is in particularbisphenol-A free and/or epoxy free and/or is a thermosetting resin.

According to an embodiment, the substrate comprises thereon a curedcoating layer, in particular a coating layer configured according to oneor more embodiments of the herein disclosed subject matter, which iscured. According to an embodiment, the cured coating layer represents(shows) an image. According to a further embodiment, the substrate has acomplex geometrical shape. Embodiments of the herein disclosed subjectmatter allow the application of the coating layer (e.g. even a coatinglayer showing an image) even to such substrates.

According to an embodiment, the cured coating layer is an at leastpartially amorphous thermoset. According to a further embodiment, thecured coating layer comprises a charge control agent. According to afurther embodiment, the cured coating layer has a glass transitiontemperature Tg of at least 50° C., in particular at least 60° C. and/orwherein in particular the glass transition temperature is in a rangebetween 40° C. and 70° C., in particular in a range between 50° C. and70° C. According to an embodiment, the glass transition temperature isin a range between 40° C. and 500° C., in particular between 70° C. and500° C.

According to an embodiment, the target surface (or the substrate or thetransfer element) is heated to an elevated temperature (above roomtemperature). In this way the application of the coating material to thetarget surface (or the substrate or the transfer element) is improved.According to an embodiment, a target heating device is provided forheating the target surface (or the substrate or the transfer element).According to another embodiment, the target surface (or the substrate orthe transfer element) is heated before feeding the target surface (orthe substrate or the transfer element) to the printing device (whichaccording to an embodiment comprises the target heating device).

Chapter 4

According to an embodiment, the coating material is configured orprovided for generating a coating layer, in particular by NIP, inparticular with a resolution higher than 100 DPI, in particular whereinthe coating layer represents an image and wherein a resolution of theimage is at least 100 DPI, the coating material comprising a curableresin.

According to an embodiment, the coating material exhibits a minimumviscosity when being heated from room temperature with a heating rate of5 Kelvin per minute up to a temperature where curing of the coatingmaterial occurs, wherein the minimum viscosity is in a range between 3Pascal seconds to 20000 Pascal seconds, in particular in a range between50 Pascal seconds and 10000 Pascal seconds and further in particular ina range between 250 Pascal seconds and 7000 Pascal seconds.

According to a further embodiment, a pill flow length of the coatingmaterial is below 350 mm at a potential curing temperature which may beused to cure the coating material, and wherein the pill flow length isdetermined by the following method:

-   -   (i) pressing an amount of 0.75 gram of the coating material into        a cylindrical pill with a diameter of 13 mm at a force of 20        kilo Newton for at least 5 seconds;    -   (ii) putting the pill of coating material on a metal sheet at        room temperature;    -   (iii) putting the metal sheet with the pill into a furnace        preheated to the potential curing temperature and tempering the        pill on the metal sheet in a horizontal position for half a        minute if the resin includes an acrylic resin component and for        one minute if the resin does not include an acrylic resin        component;    -   (iv) tilting the metal sheet to a flowing down angle of 65        degrees and maintaining the metal sheet in this position for 10        minutes at the potential curing temperature;    -   (v) measuring a maximum length of the pill on the metal sheet        and taking this maximum length as the pill flow length, in        particular after removing the metal sheet from the furnace and        cooling down the metal sheet and the coating material in a        horizontal position. According to an embodiment, the measuring        item (v) thus may be defined as “removing the metal sheet from        the furnace, cooling down the metal sheet and the coating        material in the horizontal position, measuring the maximum        length of the pill on the metal sheet and taking this length as        the pill flow length”. It should be understood that the flowing        down angle is the angle with regard to the horizontal direction        (i.e. in the horizontal position, the flowing angle is zero (0)        degrees).

According to an embodiment, the coating material exhibits a minimumviscosity and a pill flow length according to embodiments of the hereindisclosed subject matter.

According to an embodiment, the viscosity is measured by conventionalmethods and/or by using conventional apparatuses for measurement ofviscosity. For example, according to an embodiment the viscosity ismeasured with a rheometer, in particular a rotatingrheometer/viscometer.

According to an embodiment, the potential curing temperature is atemperature which is used to cure the coating layer.

According to an embodiment, a curable resin comprises a curing window,wherein for a temperature within the curing window the resin can becured (e.g. fully cured) within a reasonable time, which is alsoreferred to as curing time, e.g. within 5 minutes or within 10 minutesor within 15 minutes or within 30 minutes or within 60 minutes. Forexample, according to an embodiment, the boundaries of the curing windoware defined by temperatures which correspond to two of the curing timesmentioned above. The curing window is usually provided by a manufacturerof the resin, e.g. on a data sheet. According to an embodiment, aminimum curing temperature is measured with differential scanningcalorimetry (DSC). According to an embodiment, as a potentialtemperature it is chosen a temperature at which the gel time isreasonable, e.g. where the gel time is 5 minutes or, in anotherembodiment, 10 minutes or, in still another embodiment, 15 minutes.According to an example the minimum curing temperature is a temperatureat which the gel time is between 3 minutes and 7 minutes.

According to an embodiment, the potential curing temperature is atemperature within the curing window. According to an embodiment, forfinal curing the curing temperature is in a range which is within thelower 70% of the curing window. According to an embodiment, for finalcuring the curing temperature is in a range which is within the lower50% of the curing window or, in another embodiment, within the lower 30%of the curing window. It is noted that according to an embodiment thepotential curing temperature is different from the curing temperaturethat is used later for final curing of the coating layer.

According to an embodiment, the potential curing temperature is 180° C.According to a further embodiment the pill flow length is smaller orequal to 300 mm.

According to an embodiment, the resin includes an acrylic resincomponent in an amount of more than 50 w-% based on the overall resinamount; and the pill flow length is in a range between 180 millimeterand 300 millimeter.

According to a further embodiment, the resin includes an epoxy resincomponent in an amount of at least 50 w-% based on the overall resinamount; and the pill flow length is in a range between 15 millimeter and35 millimeter.

According to a further embodiment, the resin includes a polyester resincomponent in an amount of at least 50 w-% based on the overall resinamount; and the pill flow length is in a range between 20 mm and 180 mm.

According to a further embodiment, the resin includes a mixture of apolyester resin component and an epoxy resin component in an amount ofat least 80 w-% based on the overall resin amount; and the pill flowlength is in a range between 15 mm and 150 mm, in particular in a rangebetween 15 mm and 100 mm.

According to a further embodiment, the resin comprising an amorphousresin portion, wherein the amorphous resin portion comprising at leastone amorphous resin with functional groups that can be cured, inparticular via heat.

According to a further embodiment, the coating material comprises acrosslinking material which is capable of reacting with the at least oneamorphous resin to thereby cure the coating material; wherein inparticular the crosslinking material includes one or more materialschosen from epoxy/glycidyl-group-containing materials, includingepoxy-resins, hydroxyalkylamide hardeners, isocyanate hardener anddouble bond containing compounds with a thermal radical initiatorsystem.

According to a further embodiment, the coating material comprises theamorphous resin portion in an amount of at least 30 w-% based on theoverall amount of resin.

According to an embodiment, the coating material comprises a chargecontrol agent (CCA) in an amount of at least 0.1 w-% based on theoverall weight of the coating material, in particular at least 1 w-% andmore particularly at least 2 w-% (all based on the overall weight of thecoating material).

According to an embodiment, the coating material is free of chargecontrol agents.

According to an embodiment, the coating material is a particulatecoating material comprising (e.g. a plurality) coating materialparticles. According to an embodiment, the coating material has anaverage particle size between 1 μm and 25 μm, in particular between 5 μmand 20 μm. According to a further embodiment the coating material has ad10 value equal to or larger than 5 μm. According to a furtherembodiment, the coating material has a dl value equal to or larger than5 μm.

According to a further embodiment the coating material comprises inparticular a particle size distribution of

-   -   d10 being between 5 μm and 7 μm, and/or    -   d50 being between 8 μm and 10 μm, and/or    -   d90 being between 12 μm and 14 μm.

According to a further embodiment, wherein a mean sphericity of thecoating material particles is at least 0.7, in particular at least 0.8,further in particular at least 0.9.

According to an embodiment, the coating material comprises effectpigments, in particular with a d90 diameter of more than 150 μm, inparticular with a d90 diameter of more than 100 μm, in particular with ad90 diameter of more than 50 μm, in particular with a d90 diameter ofmore than 20 μm and more particularly with a d90 diameter of more than10 μm. According to a further embodiment, the d90 diameter is less than150 μm.

According to an embodiment, more than 50%, in particular more than 75%and further in particular more than 90% of the surface of the effectpigment is covered with a thermosetting material and which is at leastpartly transparent.

According to an embodiment, the coating material comprises a salicyliccompound, in particular a zinc salicylic compound, and/or the resincomprises a polyester resin component comprising terephtalic acid and/orisophtalic acid; and/or an acrylic resin; and/or a fluorine containingpolymer, preferably hydroxyl functional fluorine polymer; and/or whereinthe coating material comprises with respect to the entire amount ofcoating material less than 0.5 w-% of flow additive.

According to an embodiment, the image is printed with one or morecoating materials according to the herein disclosed subject matter.According to an embodiment, a final image thickness of the image is atleast 2 μm, in particular at least 10 μm, more particularly at least 20μm, more particularly at least 40 μm.

According to an embodiment, a reservoir for a NIP device is provided,the reservoir comprising a coating material according to one or moreembodiments of the herein disclosed subject matter. According to anembodiment, a cartridge for a NIP device is provided, the cartridgecomprising a coating material according to one or more embodiments ofthe herein disclosed subject matter. According to an embodiment, thecartridge is a changeable cartridge of the NIP device which provides thecoating material to the NIP device.

According to an embodiment, a NIP device is provided, the NIP devicecomprising a coating material according to at least one embodiment ofthe herein disclosed subject matter.

According to an embodiment, a transfer element is provided, the transferelement comprising a coating layer, in particular a uncured or partiallycured coating layer, generated from a coating material according to atleast one embodiment of the herein disclosed subject matter.

According to an embodiment, a substrate is provided, in particular apre-coated substrate, the substrate comprising a coating layer generatedfrom a coating material according to at least one embodiment of theherein disclosed subject matter.

According to an embodiment, a method is provided, the method comprising:applying a coating layer generated from the coating material accordingto at least one embodiment of the herein disclosed subject matter to atarget surface by means of a NIP device. According to a furtherembodiment, a method is provided, the method comprising: generating acoating layer from the coating material according to at least oneembodiment of the herein disclosed subject matter on a target surface,in particular by means of a NIP device.

According to an embodiment, a coating layer application device isprovided, the coating layer application device being configured forreceiving a transfer element according to at least one embodiment of theherein disclosed subject matter, the coating layer application devicebeing further configured for applying the coating layer to a substrate.

According to an embodiment, a use of a coating material is provided, inparticular a use of a coating material according to at least oneembodiment of the herein disclosed subject matter. According to anembodiment, the coating material is used for applying a coating layer toa target surface, in particular by means of a NIP device.

Chapter 5

According to an embodiment, a coating material is provided, the coatingmaterial being processable by NIP to form at least a part of a coatinglayer representing an image; the coating material comprising anamorphous resin portion and being curable; the coating material beingconfigured for being applied with a thickness of at least 15 μm.

It is noted, that generally herein the terms “representing an image” and“exhibiting a pattern” are used synonymously and can be interchangedwith each other.

According to an embodiment, the image comprises at least two differentcolors. According to another embodiment, the image comprises only asingle color.

According to an embodiment, the coating layer which represents the imageis a coating layer made from a uniform coating material. According toanother embodiment, the coating layer may include two or more differentcoating materials. According to an embodiment, the coating layerincludes only a single color. According to further embodiments, thecoating layer may include two or more colors.

According to an embodiment, the NIP method is an electrophotographicprinting method, which is used for example in conventional laserprinters or LED printers. A respective NIP unit may be hence referred toas electrophotographic printing unit. According to an embodiment (and asis the case e.g. for electrophotographic printing) a single coatinglayer that is provided from the printing unit may have a thickness inthe range between 1 μm to 40 μm, in particular 4 μm to 15 μm and furtherin particular 6 μm to 10 μm. According to an embodiment, the thicknessof a single coating layer is in a range between 5 μm to 8 μm. Accordingto an embodiment, the thickness of a single coating layer is in a rangebetween 15 μm to 20 μm.

According to an embodiment, several coating layers may be printed overeach other. In particular, according to an embodiment a further coatinglayer is printed over an existing coating layer without curing orheating (in particular substantial heating) the existing coating layer.However, according to an embodiment, pressure is applied to the furthercoating layer and the existing coating layer to press both layers ontoeach other. The pressure applied in this way may be comparatively low inorder not to blur the printed dots but may be helpful to provide astable application of the further coating layer onto the existingcoating layer.

In accordance with an embodiment, the coating material is configured forbeing applied with a thickness of at least 15 μm. In particular, thecoating material is configured for being applied with a thickness of atleast 15 μm without curing or inducing viscous flow in one or morecoating layers. For example, if an individual coating layer has athickness of 5 μm in accordance with the aforementioned embodiments thecoating material is configured for being applied in three coating layers(which may be referred to as layer package in some embodiments) withoutcuring or inducing viscous flow in one or more coating layers. This issurprisingly achieved by a coating material according to one or moreembodiments of the herein disclosed subject matter.

According to an embodiment, the coating material is configured for beingapplied with a thickness of at least 20 μm, in particular with athickness of at least 30 μm, further in particular with a thickness ofat least 40 μm.

According to an embodiment, the coating material is provided in the formof a plurality of particles wherein a ratio of an average particlediameter to a thickness of the coating layer is smaller than 1:2, inparticular smaller than 1:3, further in particular smaller than 1:4.Such ratios may provide for a high quality print in combination withchemical and wheathering stability due to a very compact cured layer.

According to a further embodiment, wherein the coating material has amaximum concentration of 10 w-% of bisphenol A and/or epoxy resin withrespect to the entire coating material, in particular a maximumconcentration of 5 w-% of bisphenol A and/or epoxy resin with respect tothe entire coating material, and is in particular bisphenol A freeand/or epoxy free, wherein in particular the coating material comprisesone or more of a polyester resin, an acrylic resin, a fluorinecontaining resin (e.g. Lumiflon resin), and a polyurethane resin.

According to an embodiment the polyester resin comprises an(incorporated) acid monomer and wherein at least 10 w-% of the acidmonomer is isophthalic acid, in particular at least 20 w-% of the acidmonomer is isophthalic acid, in particular at least 30 w-% of the acidmonomer is isophthalic acid, in particular at least 50 w-% of the acidmonomer is isophthalic acid; in particular at least 80 w-% of the acidmonomer is isophthalic acid, and further in particular at least 85 w-%of the acid monomer is isophthalic acid.

According to a further embodiment, a minimum glass transitiontemperature of the coating material, in particular of the uncuredcoating material, is above 40° C., in particular above 50° C., inparticular above 60° C., for the cured one the Tg is above 50° C., inparticular above 60° C., more particularly above 70° C., and moreparticularly above 80° C.

According to an embodiment, the remaining gloss after 300 hours of UVexposure (or in other embodiments after 600 h of UV exposure or 1000 hof Xenon exposure) according to the GSB International AL 631—Part VIISegment 20.1 Kurzbewitterung UV-B (313) is at least 50%. For example, ifthe coating material comprises a polyester resin, a concentration of(incorporated) isophthalic acid (with regard to the acid monomer in thepolyester resin) may be chosen high enough to achieve the specifiedvalues of remaining gloss. Further, for example if the coating materialcomprises fluorine containing resin (fluoropolymer) and/or acrylicresin, the concentration of these resins may be chosen high enough toachieve the specified values of remaining gloss.

According to an embodiment, the remaining gloss after 300 hours of UVexposure according to GSB international AL631-PartVII-segment 20.1Kurzbewitterung UV-B (313) is at least 50%, in particular at least 85%;a remaining gloss after 600 hours of UV exposure according to the testprocedure of GSB international AL631-PartVII-segment 20.1Kurzbewitterung UV-B (313) is at least 50%, in particular at least 85%;a remaining gloss after 1000 hours of Xenon exposure according to EN ISO16474-2 determined according to ISO 2813, is at least 50%, in particularat least 85%.

According to an embodiment, the coating material is configured to,besides forming a part of a coating layer representing an image, servein addition at least one of the following functions: sealing,high-temperature resistance, weathering resistance, long-termultraviolet stability, wearing coat, being free from pinholes (inparticular being substantially free from pinholes), wear based bleachingprotection, outdoor capability, scratch resistance, resistance tosolvents, diffusion reduction, corrosion protection.

According to an embodiment, the coating material comprises an amount of0.1 w-% to 10 w-%, in particular 0.5 w-% to 5 w-%, in particular 0.8 w-%to 2.5 w-%, in particular 0.8 w-% to 1.3 w-%, e.g. 1 w-%, and inparticular at least 2 w-% of a charge control agent. According to anembodiment, the charge control agent comprises or consists of one ormore salicylic acid zinc compounds (zinc salicylic compounds). Such acharge control agent has shown to provide a surprising performance.However, according to other embodiments, other conventional chargecontrol agents may be used, such as T99 from Hodogaya.

According to an embodiment, the coating material is a powdery coatingmaterial which is at least partly, in particular fully thermallycurable.

According to an embodiment, a reservoir for a NIP device is provided, inparticular a cartridge for a nonimpact impact printing device, thereservoir comprising in particular a coating material according to atleast one embodiment of the herein disclosed subject matter.

According to an embodiment, there is provided a NIP device, inparticular comprising a coating material according to one or moreembodiments.

According to an embodiment, a processing system (which may also referredto as processing device) is provided, the processing system comprising acoating material according to one or more embodiments of the hereindisclosed subject matter and further comprising a NIP device beingconfigured for printing the coating material.

According to an embodiment, the NIP device is configured for generatingfrom the coating material a coating layer, in particular on a transferelement.

According to a further embodiment, the processing system furthercomprises: a coating layer application device being configured forreceiving the transfer element; and the coating layer application devicebeing further configured for applying the coating layer on the transferelement to a substrate.

According to an embodiment, the NIP device is configured for generatinga coating layer from a coating material on a substrate.

According to a further embodiment, the processing system furthercomprises a curing device, for curing, in particular final curing, ofthe coating layer on the substrate.

According to a further embodiment, a transfer element is provided, thetransfer element comprising in particular a coating layer generated froma coating material according to one or more embodiments of the hereindisclosed subject matter or a coating layer generated from at least onecoating material with comparable thermal expansion coefficient and/orfree functional groups able to react with the coating material accordingto the invention.

According to a further embodiment, a substrate is provided, inparticular a pre-coated substrate, the substrate comprising a coatinglayer generated from a coating material according to one or moreembodiments of the herein disclosed subject matter.

According to a further embodiment, the substrate further comprises abase coat (below the coating layer, also referred to as pre-coating)and/or a top coat (above the base coat and/or above the coating layer).

According to an embodiment, a method is provided, the method comprising:applying a coating layer, generated from the coating material accordingto one or more embodiments of the herein disclosed subject matter, to atarget surface, in particular by means of a NIP device.

According to an embodiment, a computer program product comprises aprogram element, the program element being adapted for, when executed ona processor device, performing the method according to aforementionedmethod.

According to an embodiment, a coating layer application device isprovided, the coating layer application device being configured forreceiving a transfer element comprising a coating layer generated from acoating material according to one or more embodiments of the hereindisclosed subject matter, the coating layer application device beingfurther configured for applying the coating layer to a substrate.

According to an embodiment, there is provided a use of a coatingmaterial for applying a coating layer according to one or moreembodiments of the herein disclosed subject matter to a target surface,in particular by means of a NIP device.

Chapter 6

According to an embodiment, a NIP device is provided, the NIP devicecomprising: a coating material being curable and comprising a resin; aprinting unit, in particular a electrophotographic printing unit, beingconfigured for printing the coating material so as to form a coatinglayer, wherein the coating layer forms at least part of a layer packagecomprising at least one layer; the NIP device being configured forproviding the layer package so as to define a surface structure with thelayer package; wherein the surface structure is defined by a thicknessvariation of the layer package; wherein the thickness variation is in arange between 1 μm and 1000 μm, in particular in a range between 1 and300 μm, and is in particular more than 1 μm, in particular more than 5μm, in particular more than 10 μm and in particular more than 20 μm.

According to an embodiment, the coating material comprises an amorphousresin portion in an amount of at least 30 w-% based on the overallamount of resin. According to a further embodiment, the coating materialcomprises with respect to the entire amount of coating material lessthan 0.5 w-% of flow additive. According to a further embodiment, thecoating material comprises with respect to the entire amount of coatingmaterial less than 0.4 w-%, less than 0.3 w-% or preferably less than0.1 w-% of the flow additive.

According to an embodiment, a flow additive (or leveling agent, bothterms may be used synonymously) is a flow addititve which influences theviscosity (in particular of the uncured coating material) and/or asmoothness of a surface of the coating layer (in particular of the atleast partially cured coating layer or of a coating layer which wassubjected to a temperature range in which the uncured coating materialis in its supercooled liquid state). With small thickness variations,e.g. in the range of several micrometer, variations in the gloss of thecoating layer may be introduced. Depending e.g. on the magnitude of thethickness variations and/or geometrical shape of the surface structuredifferent appearances of the coating layer (and also of the curedcoating layer on the substrate) may be provided.

According to an embodiment, the NIP device is configured for providingthe layer package with a varying thickness such that a first packageportion of the layer package at a first position has a first thicknessand a second package portion of the layer package at a second positionhas a second thickness.

According to a further embodiment, the printing unit is configured forselectively printing the coating material depending on a lateralposition in a plane of the coating layer.

According to an embodiment, the NIP device is configured for printing afurther coating layer, in particular from the coating material, as apart of the layer package. According to a further embodiment, thecoating layer and the further coating layer have a different spatialcoverage. According to a further embodiment, the coating layer and thefurther coating layer overlap each other, resulting in a thicknessvariation within the layer package. According to a further embodiment,the coating layer and the further coating layer have functional groupswhich can react with each other to thereby attach adjoining regions ofthe coating layer and the further coating layer.

According to an embodiment, the printing unit is configured for printingof the further coating layer.

According to a further embodiment, the printing unit is a first printingunit and a different, second printing unit is provided, the secondprinting unit being configured for the printing of the further coatinglayer. According to an embodiment two or more printing units may beprovided for printing the same coating material. This may improve thespeed of the printing process necessary to provide the desired layerpackage. In other embodiments, two or more printing units may beprovided for printing different coating material.

According to an embodiment, the NIP device is configured for printing acoating material in at least two touching layers in particular whereinthe two touching layers include the coating layer and the furthercoating layer, in particular wherein the two touching layers havefunctional groups capable of reacting with each other. According to anembodiment, the coating layer and the further coating layer are formedfrom the same or different coating materials of a set of coatingmaterials in particular a set of coating materials which define at leasta CMYK color system. In other words, according to an embodiment the NIPdevice is configured for printing a set of coating materials whichdefine at least a CMYK system (i.e. the set of coating materials definesa CMYK system and optionally comprises further coating materials (e.g. atransparent coating material, at least one effect coating material, atleast one white coating material).

According to an embodiment, the NIP device comprises a structuringdevice, the structuring device being configured for imposing a heightprofile into the layer package, in particular by pressure, such as bypressing an embossing element into the layer package, further inparticular by energy transfer such as the transfer of radiation energy,in particular by means of a laser beam (e.g. by a pulsed laser beam),into the layer package to evaporate part of the layer package.

According to an embodiment, the printing unit is configured forproviding the coating layer with a resolution in the layer plane of thecoating layer of more than 2 l/mm, in particular more than 5 l/mm andfurther in particular more than 10 l/mm.

According to an embodiment, the printing unit is configured forproviding the coating layer with a resolution perpendicular to the layerplane of the coating layer of more than 2 l/mm, in particular more than5 l/mm and further in particular more than 10 l/mm and further inparticular with more than 20 l/mm.

According to an embodiment, the printing unit is configured forproviding the coating layer with a resolution (in the layer plane and/orperpendicular to the layer plane) so as to establish by the applicationof the coating layer a height difference of at least 10 μm, inparticular of at least 5 μm within a lateral distance of less than 254μm, in particular less than 85 μm and more in particular less than 42μm.

According to an embodiment, the coating layer is generated as aplurality of dots (as this is typical for NIP/digital printing such aslaser printing). Hence, if the coating layer is provided with aresolution of 100 dpi, the diameter of a dot is about 254 μm. Hence, aheight difference of 5 μm (corresponding to a thickness variation of 5μm) within the lateral distance of less than 254 μm corresponds to aheight difference that is achieved with a coating layer of 5 μmthickness and the resolution of 100 dpi.

According to an embodiment, a color in the coating layer (the coatinglayer may comprise a single color or two or more different colors(coating materials)) extends continuously from a top surface of thecoating layer to a bottom surface of the coating layer.

According to an embodiment, the layer package exhibits a thicknessvariation of at least 1 μm, in particular at least 5 μm and further inparticular at least 10 μm. In particular in combination with differentcolors continuously extending through the coating layer, a wheatherresistant image with pronounced haptic effect may be achieved.

According to an embodiment, the layer package forms an image on thetarget surface.

According to a further embodiment, the layer package includes at leastone void leaving the target surface at the position of the voiduncovered.

According to an embodiment, a smallest lateral dimension of the surfacestructure is above 500 μm, in particular above 200 μm and further inparticular 100 μm. This may provide for a tactile surface structure. Itis noted that a smallest possible lateral dimension of the surfacestructure depends on the resolution of the printing process (e.g. on adot size of the printing process).

According to a further embodiment, a substrate is provided, inparticular a precoated substrate, the substrate comprising a layerpackage, the layer package being cured and comprising at least onecoating layer. According to an embodiment, a thickness of the layerpackage exhibits a variation in a range between 1 μm and 1000 μm, inparticular in a range between 1 and 300 μm, in particular more than 5μm, in particular more than 10 μm and in particular more than 20 μm andwherein the layer package defines a surface structure.

According to an embodiment, a cured coating layer (generated from acoating material according to embodiments of the herein disclosedsubject matter) comprises with respect to the entire amount of coatingmaterial of the coating layer less than 1 w-%, in particular less than0.5 w-%, further in particular less than 0.4 w-%, less than 0.3 w-% andpreferably less than 0.1 w-% of flow additive.

For example, according to an embodiment the at least one coating layerof the cured layer package comprises with respect to the entire amountof coating material of the coating layer less than 0.5 w-% (or less thanany other amount specified herein, e.g. less than 0.4 w-%) of flowadditive.

According to a further embodiment, a thickness of the layer packagevaries over the substrate, and in particular wherein a first packageportion of the layer package at a first position has a first thicknessand a second package portion of the layer package at a second positionhas a second thickness; and/or wherein the layer package includes atleast one void leaving a surface of the substrate at the position of thevoid uncovered.

According to an embodiment, the layer package defines a surfacestructure. According to a further embodiment, a smallest lateraldimension of the surface structure is below 254 μm, in particular below85 μm and further in particular below 42 μm. According to a furtherembodiment, the layer package has a curing degree that the image is ableto reach a rating of at least 2-3 in the Methylethylketone test after 10s according to the DIN EN 12720 and/or the image resists at least 50 IPA(Isopropyl alcohol) double rubs and/or the image resists at least 5acetone double rubs, in particular at least 10 acetone double rubs, inparticular at least 20 acetone double rubs.

According to an embodiment, the layer package comprises a minimumarithmetic average roughness of larger or equal than 1 μm (Ra≥1 μm), inparticular larger or equal than 3 μm (Ra≥3 μm) and further in particularlarger or equal than 5 μm (Ra≥5 μm); and/or a maximum thickness of thelayer package being at least 2 μm, in particular 10 μm, further inparticular 20 μm and further in particular 40 μm.

According to an embodiment, the substrate and in particular the curedlayer package on the substrate fulfills the requirements of Qualicoatclass 1 and/or Qualicoat class 2 as defined in a specification forquality label for liquid and powder organic coatings on aluminum forarchitectural applications, 14 edition, approved on 6 Nov. 2014 andeffective from 1 Jan. 2015, available from www.qualicoat.net.

According to a further embodiment, the surface of the substratecomprises a maximum arithmetic average roughness of equal or less thanone micrometer (Ra≤1 μm), in particular equal or less than 0.5micrometer (Ra≤0.5 μm) and further in particular equal or less than 0.2μm (Ra≤0.2 μm), where a defined surface roughness of the substrate wascompensated via an image of the preceding features.

According to a further embodiment, the layer package having a resolutionof at least 100 DPI, in particular of at least 300 DPI, and further inparticular of at least 600 DPI.

According to an embodiment, at least one coating layer has freefunctional groups capable of reacting with other layers and/or thesubstrate, in particular including a pre-coat on the substrate and/or atop coat in particular before the curing. Hence, according to anembodiment the substrate comprises a precoat and the free functionalgroups of the coating layer are capable of reacting with the precoat.According to a further embodiment, a top coat is applied to the at leastone coating layer and wherein the coating layer has free functionalgroups capable of reacting with the top coat. According to anembodiment, the topcoat is applied before curing.

According to an embodiment, a method is provided, the method comprising:providing a layer package to a target surface, the layer packagedefining a surface structure and a thickness of the layer package, thelayer package comprising at least one layer; the surface structure beingdefined by a thickness variation of the layer package; and the thicknessvariation being in a range between 1 μm and 1000 μm, in particular in arange between 1 and 300 μm, in particular more than 5 μm, in particularmore than 10 μm and in particular more than 20 μm; wherein providing thelayer package includes printing a coating material so as to form acoating layer, the coating layer forming a layer of the layer package,and the coating material being curable and comprising a resin, and theprinting being performed by using a NIP method, in particular anelectrophotographic printing method. In accordance with embodiments ofthe herein disclosed subject matter, the coating material comprises anamorphous resin portion in an amount of at least 30 w-% based on theoverall amount of resin, and the coating material comprises with respectto the entire amount of coating material less than 0.5 w-% (or less thanany other amount specified herein, e.g. less than 0.4 w-%) of flowadditive.

According to an embodiment, the coating layer is a first coating layer,the method further comprising printing of least one further coatinglayer by performing a layer by layer printing, wherein in particulareach of the first coating layer and the at least one further coatinglayer has a maximum thickness of at least 1 μm, in particular of atleast 2 μm, further in particular of at least 4 μm, further inparticular at least 10 μm, further in particular at least 20 μm.

According to an embodiment, layers of the layer package which arecontacting each other in a contact region have free functional groups toreact with each other in the contact region before or during curing, inparticular wherein one or more existing layers are not cured or are atleast only partly cured in the contact region before a further layer isapplied which makes contact to the contact region of the one or moreexisting layers.

According to an embodiment, the coating material is provided as aplurality of particles, and wherein the coating material comprises anaverage powder particle size in a range between 1 μm and 25 μm, inparticular in a range between 5 μm and 20 μm and in particular whereinthe coating material has a d10 value in a range of 5 μm to 7 μm, a d50value in a range of 8 μm to 10 μm and a d90 in a range of 12 μm to 14μm.

According to an embodiment, a sphericity of the particles is at least0.7, in particular at least 0.8, further in particular at least 0.9.

According to an embodiment, the coating material comprises effectpigments with a diameter of less than 50 μm, in particular less than 20μm and further in particular less than 10 μm and, where more than 50%,in particular more than 75% and further in particular more than 90% ofthe surface of the effect pigment is covered with a thermosettingmaterial which is in particular not electrically conductive.

According to an embodiment, there is provided a reservoir, in particulara cartridge, for a NIP device according to embodiments of the hereindisclosed subject matter, the reservoir comprising a coating materialfor printing of the coating layer.

According to another embodiment a NIP device comprises a set ofreservoirs with the same or different coating materials, preferablydifferent coating materials defining at least a CMYK system, further inparticular comprising at least one coating material of a further colorand/or white and/or transparent and/or effect coatings. According to anembodiment, a NIP device comprises two or more (e.g. four) reservoirscontaining the same coating material. According to an embodiment each ofthe reservoirs of the set of reservoirs may be associated with aseparate printing unit. In case of two or more reservoirs containing thesame coating material the NIP device thus allows an increased depositionrate for the coating material per time unit.

According to an embodiment, there is provided a transfer elementcomprising a layer package, the layer package being uncured or onlypartially cured and comprising at least one coating layer, wherein athickness of the layer package is in a range between 1 μm and 1000 μmand wherein the layer package defines a surface structure. In accordancewith embodiments of the herein disclosed subject matter, the at leastone coating layer of the layer package comprises an amorphous resinportion in an amount of at least 30 w-% based on the overall amount ofresin, and wherein the coating layer comprises with respect to theentire coating layer (i.e. with respect to the entire amount of coatingmaterial of the coating layer) less than 0.5 w-% (or less than any otheramount specified herein, e.g. less than 0.4 w-%) of flow additive.

A multilevel method may be employed for providing a surface structure.Such a multilevel method is originally based on a method using grayshades but may be employed for providing the structured surface asdescribed herein. Additionally or alternatively, a multilayer method maybe employed for providing the surface structure. A multilayered methodis usually employed to combine a variety of different colors therebycreating a wider range of a different color tones. Instead of providingdifferent colors, according to a preferred embodiment, at least two ofthe color channels are exploited by using them with a single colormaterial providing differentiation in the height and/or thickness of thematerial layer. According to a further preferred embodiment, at leasttwo of the color channels are exploited by using them with a singlecolor and/or a transparent material providing differentiation in theheight and/or thickness of the material layer. According to a furtherpreferred embodiment, at least two of the color channels are exploitedby using them with a single color and/or a transparent materialproviding differentiation in the haptics and/or gloss of the materiallayer.

According to a preferred embodiment, a plurality of different layers isapplied successively, i.e. at least one first layer and thereupon asecond layer is formed. According to a further preferred embodiment, thedescribed process comprises a compression step which may be achieved byraising temperature and/or pressure. Preferably such a compression stepis carried out at least between the creation of a first and a secondlayer.

According to an embodiment, the non-impact printing device is configuredand may be used for generating a surface structure having a Lotus typeeffect. Haptic perception is the ability to grasp something, inparticular to feel a certain surface profile. Tactile perception isrelated to haptic perception. While haptic perception is achievedthrough the active exploration of surfaces and objects, tactileperception is achieved through the passive exploration of surfaces andobjects, i.e. no movement over the surface is required to triggertactile perception. By the coating and the corresponding method asdisclosed in the present application, in particular by means of thedescribed relief printing process, suitable surfaces capable oftriggering haptic or tactile perception may be generated. In particular,the non-impact printing device is configured and may be used forgenerating a braille type surface structure. According to an embodiment,the non-impact printing device is configured and/or may be used forgenerating a surface structure having a Lotus type effect. The lotuseffect is the result of ultrahydrophobicity as exhibited by the leavesof Nelumbo or “lotus flower”. It has been found that the Lotus typesurfaces can be exploited in such a way that they have a self-cleaningeffect. Therefore, there is a significant interest in providing suitableartificially manufactured surface structures having such a Lotus typeeffect. By making use of the coating material and the correspondingmethod as disclosed in the present application, in particular by meansof the described relief printing process, suitable surfaces having apronounced Lotus type effect may be created. In particular it ispossible by means of the described relief printing process to provide aself-cleaning, i.e. a Lotus type super hydrophobic surface, with acontact angle of 160° or even more. By means of the described reliefprinting process is possible to provide such advantageous structuresefficiently, with the structures being stable, in particular resistantto degradation. According to an embodiment, the non-impact printingdevice is configured and may be used for generating a surface structureof having the plurality of channels. Such plurality of channels mayadvantageously provide humidifying effects and cooling effects bycorresponding sucking in of suitable fluids, by capillary action.

According to an embodiment, the non-impact printing device is configuredand may be used for generating a shark-skin effect.

According to an embodiment, the non-impact printing device is configuredand may be used for generating a surface structure which is suitable forchanging laminar or turbulent streams coming into contact with saidsurface. Stated differently the non-impact printing device may createsurfaces which can be individually designed for triggering orcontrolling streams of a fluid (e.g. a gas or a liquid). Additionally,surfaces may be individually designed to reduce negative acousticeffects. Conversely surfaces may be individually designed to induce oramplify acoustic effects.

According to an embodiment, the non-impact printing device is configuredand may be used for generating a surface having a color gradient withrespect to the direction corresponding to the coating layer thickness,i.e. the thickness of the surface structure. By making use of such agradient it is for instance possible to provide an indication for theabrasion of materials as caused by harsh weather conditions. Forinstance, the layer may be provided having a color gradient, i.e. thecolor becoming more intense with increasing distance from the layersurface. When abrasion occurs, the color intensity being exposed to theouter surface of the layer becomes more and more intensive, therebyindicating the progress of the abrasion process of the surface layer.

According to an embodiment, the surface structure is configured so as togenerate interference (in particular interference colors) inelectromagnetic radiation, in particular in visible light. According toa further embodiment, the surface structure is configured so as toreceive incoming light and provide outgoing light, wherein the colordistribution of the incoming light and the outgoing light is different,in particular different due to interference.

According to an embodiment, the non-impact printing device is configuredand may be used for selectively generating a surface only on certainparts of the substrate. For instance, the surface as obtained by thedescribed relief printing method may be only applied to areas which areparticularly exposed to mechanical stress. For instance by means of thedescribed relief printing it is possible to selectively provide acoating on handles, rails and tracks in the machines or machinecomponents which are usually exposed to high mechanical stress. It isalso part of the described concept to provide coatings with a differentthickness in different substrate regions depending on the mechanicalstress the different regions are usually exposed to. Surface coatingsfor a plurality of substrate structures in a variety of different fieldsof technology can be efficiently provided. The more mechanicallystressed a certain region of substrate is, the thicker the coating layerapplied should be. On the one hand, this allows for protecting the mostmechanically stressed regions of substrate, while on the other hand theamount of material used for providing the coating can be reduced. Stateddifferently, by means of the process is possible to achieve suitableprotection against mechanical stress at an optimized cost efficiency. Onthe other hand thickness can be reduced at regions where a highmechanical flexibility is required, in particular if weatheringresistance is not that critical.

According to an embodiment, the non-impact printing device is configuredand may be used for generating a surface structure by applying twodifferent coatings i.e. at least one second coating layer (or furthercoating layer) is placed on and/or adjacent to at least one firstcoating, wherein the at least one first coating layer is preferably indirect physical contact with the at least one second coating layer. Bymeans of such a structure is possible to exploit the advantages of aninteraction of the first coating layer with the second coating layer andvice versa. In more particular embodiment, the first coating layer issuitable for adhering to the substrate on which the surface of structureis to be formed. The second coating layer may be configured forexhibiting an advantageous surface effect as for example a Lotus typeeffect or shark skin effect. However, the second coating layer may beless suitable for adhering to the substrate surface but instead beingcapable of forming a suitable connection to the at least one firstcoating layer. By providing a first coating layer which strongly bindsto the substrate to be coated and by providing upon the first coatinglayer a second coating layer exhibiting a desired surface effect andstrongly binds to the first coating layer, it is possible to provideindividually designed surfaces for a plurality of different substrates.An adherence or a capability of connection of the first coating layerand the second coating layer may be achieved by suitably choosing thesuitable coating materials for the first coating layer and the secondcoating layer. In particular, the first coating layer may comprise acoating material having a first functional group which is capable ofinteracting, in particular forming a chemical bond by a chemicalreaction, with a second coating material as comprised in the secondcoating layer. In addition to a chemical reaction between the firstcoating layer and the second coating layer, connecting of the firstcoating layer and the second coating layer may be achieved by physicaleffects such as adherence and that the like. In the above and generallyherein, instead of a second (or further) coating layer a layer packagecomprising a coating layer may be employed.

According to a further embodiment, the non-impact printing device isconfigured and may be used for generating a surface structure byapplying three different coating layers i.e. at least one second coatinglayer being placed on and/or adjacent to at least one first coatinglayer and least one third coating layer being placed on and/or adjacentto the at least one second coating layer. By means of such a structureis possible to exploit the advantages of an interaction of the firstcoating layer with the second coating layer and the third coating layerand with the substrate.

According to a further embodiment, the non-impact printing device isconfigured and may be used for generating a surface structure byapplying three or more different coating layers i.e. at least one secondcoating layer being placed on and/or adjacent to at least one firstcoating layer and least one third coating layer being placed on and/oradjacent to the at least one second coating layer. By means of such astructure is possible to exploit the advantages of an interaction of thefirst coating layer with the second coating layer and the third coatinglayer and with the substrate.

Chapter 7

According to an embodiment, there is provided a coating material, inparticular for generating a coating layer by NIP, the coating materialbeing provided in the form of particles and comprising: a curable resinpreferably an at least partially thermal curable resin and even more inparticular curable by a crosslinking agent able to react with functionalgroups of the resin, the resin comprising in particular an amorphousresin portion; wherein an average diameter of the particles is in arange between 1 μm and 25 μm; and wherein the particles have an averagesphericity larger than 0.7, in particular larger than 0.8, in particularlarger than 0.9.

According to an embodiment, there is provided a developer comprising: acarrier; and, in an amount of 10 wt-% or less (based on the total amountof developer), a coating material, in particular a coating material forgenerating a coating layer by non-impact printing, the coating materialbeing provided in the form of particles and comprising: a curable resinpreferably an at least partially thermal curable resin and even more inparticular curable by a crosslinking agent able to react with functionalgroups of the resin, the resin comprising in particular an amorphousresin portion; wherein an average diameter of the particles is in arange between 1 μm and 25 μm; wherein the particles have an averagesphericity larger than 0.7, in particular larger than 0.8, in particulara sphericity larger than 0.9; wherein, if the coating material is heatedfrom room temperature with a heating rate of 5 K per minute, the coatingmaterial upon heating reduces its viscosity down to a minimum viscosityand increases its viscosity upon further increase of the temperature;wherein the minimum viscosity is in a range between 3 Pascal seconds and20000 Pascal seconds.

According to an embodiment, the cross-linking agent may be of the sametype or may even be the same material as the curable resin or a resincomponent thereof.

Generally the sphericity (S) of a particle is defined as the ratio of asurface area (As) of a sphere of the same volume as the particle overthe surface area of the particle (Ap). Hence S=As/Ap. However, as thesurface area of the particle may be difficult to measure, in particularfor a plurality of particles, sophisticated methods have been developedwhich are implemented in commercially available apparatuses, as forexample Sysmex FPIA-3000, available from Malvern Instruments GmbH,Germany, www.malvern.com.

According to an embodiment, the average sphericity is defined byaveraging a circularity of the particles (i.e. by the averagecircularity of the particles), wherein the circularity of a particle isdetermined by a circumference of a circle having an area that is equalto largest area enclosed by a perimeter of the particle divided by theperimeter.

According to an embodiment, the average sphericity is defined so as toinclude only a portion of the particles for calculating the averagesphericity, in particular a portion of the particles which includes thelargest particles of the coating material up to an amount of 80% of theoverall coating material.

According to a further embodiment, the mean sphericity is between 0.90and 0.97, preferably 0.93 to 0.97. It is noted that according to anembodiment, a sphericity of 1.0 (spherical particles) is not desired. Inaccordance with an embodiment, a sphericity higher than 0.98 may provideless contact points of the coating material particles to the carrierparticles, leading to slower charging of the coating material particlesand/or may result in a more difficult cleaning of the excess (nottransferred) coating material particles on the organic photo conductor,OPC (if an OPC is used) after the transfer.

According to an embodiment, a set of developers is provided, whereineach developer is configured according to one or more embodiments of theherein disclosed subject matter and wherein the set of developersprovides at least a CMYK system (CMYK=cyan, magenta, yellow, and key(black)).

According to an embodiment, the coating material of each developer has adl value equal to or larger than 5 μm and/or the coating material ofeach developer has an average sphericity in a range between 0.90 to0.97, in particular between 0.93 and 0.97.

Further according to an embodiment, a set of coating materials isprovided, wherein each coating material is configured according to oneor more embodiments of the herein disclosed subject matter and whereinthe set of coating materials provides one or more color systems, e.g. atleast a CMYK system.

Possible applications may include e.g. high resolution monocolor logosor barcodes or phosphorescent/fluorescent images, just to name someexamples.

According to an embodiment, each coating material of the set has a dlvalue equal to or larger than 5 μm and/or each coating material of theset has an average sphericity in a range between 0.90 to 0.97, inparticular between 0.93 and 0.97.

According to embodiments of the herein disclosed subject matter a CMYKsystem of curable compatible coating materials is provided that allow ahigh resolution color print of the curable coating materials.

According to a further embodiment, the coating material is curableand/or comprises a charge control agent and/or a silicon compound, inparticular SiO2 (=silica) and/or a titanium compound in particular TiO2(=titania). According to a further embodiment, the particle sizedistribution of the silicon compound and/or the titanium compound has ad50 value in a range between 1 nm and 100 nm, in particular in a rangebetween 3 nm and 50 nm. According to a further embodiment, the coatingmaterial comprises the silicon compound and/or the titanium compound inparticular in an amount of more than 0.5 w-%, in particular more than 1w-% and further in particular more than 1.5 w-%.

According to a further embodiment, the charge control agent includeszinc salicylic compounds in particular Zinc Salicylate. According to afurther embodiment, the coating material comprises the charge controlagent, with respect to the entire coating material, in an amount of lessthan 10 w-%, in particular less than 3.5 w-% and further in particularless or equal than 2 w-% and in particular higher than 1 w-%.

According to a further embodiment, the coating material is at leastpartially curable by radiation, in particular ultraviolet radiationand/or x-ray radiation and/or electron beam.

According to a further embodiment, the resin comprises thermosettingresin, and wherein the thermosetting resin is at least partly curable inparticular by a reaction not including double bonds.

According to a further embodiment, if the coating material is heatedfrom room temperature with a heating rate of 5 K per minute, the coatingmaterial upon heating reduces its viscosity down to a minimum viscosityand increases its viscosity upon further increase of the temperature;and wherein the minimum viscosity is in a range between 3 Pascal secondsand 20000 Pascal seconds, in particular in a range between 50 Pascalseconds and 10000 Pascal seconds and further in particular in a rangebetween 250 Pascal seconds and 7000 Pascal seconds.

According to an embodiment, the coating material comprises anaccelerator (e.g. a catalyst) which accelerates the curing (i.e.increases the curing rate compared to the composition withoutaccelerator).

According to an embodiment, the accelerator is configured foraccelerating the reaction between the carboxyl groups and the epoxygroups and/or for epoxy homopolymerization. According to an embodiment,the accelerators/catalysts disclosed in WO2001/092367 A1 (the entiredisclosure of which is incorporated herein by reference) may be used.

A suitable catalyst comprises one or more of the following:

imidazole (e.g. “2-methyl imidazole”, “2-ethyl imidazole”, “propylimidazole”, “2-isopropyl imidazole”, “2-phenyl imidazole”, “2-undecylimidazole”, “2-heptadecyl imidazole”,“1-((2-methyl-1H-imidazole-1-yl)methyl)naphthalene-2-01”),

imidazoline (such as “2-phenyl-2-imidazoline”),

tertiary amines (such as “2,4,6-tri-(dimethylaminomethyl)phenole,“N,N-dimethyl stearylamine”),

phosphonium salts (such as “tetrabutylphosphonium bromide”,“butyltriphenylphosphonium chloride”, “butyltriphenylphosphoniumbromide”, “ethyltriphenylphosphonium bromide”),

ammonium compounds (such as “benzyltrimethylammonium bromide”,“tetraethylammonium benzoate”, “choline chloride”),

urone (such as “fenurone”, “diurone”, “chlorotolurone”, “TDI urone”),

guanidine (such as “ortho-tolylbiguanide”),

zinc compounds (such as “zincacetyl acentonate”, “zinc2-ethylhexylphosphate salt”).

Catalysts may also be used in the form of adducts (such as imidazoleadduct, imidazoline adduct). The catalysts (such as imidazole,imidazoline, phosphonium salt) may also be added to polyester resinsduring resin synthesis.

Currently preferred as catalyst is “2-phenyl-2-imidazoline” (such as“Eutomer B31” of Eutec Chemical Co.). However also combinations of thiscatalyst with one or more of the above mentioned catalysts, preferablywith imidazole(s) (e.g. 2-ethylimidazole) or phosphonium salts (such asethyltriphenylphosphonium bromide), may be used. In this way a coatingmaterial may be achieved which is highly reactive and at the same timestable during storage (storage stability). By combination of theseaccelerator types it is possible to achieve more stable coatingmaterials which exhibit an improved storage stability even in thepresence of variations in the homogeneity of the composition of thecoating material.

According to an embodiment, the coating material has a maximumconcentration of 10 w-% of bisphenol A and/or epoxy resins with respectto the entire coating material, in particular a maximum concentration of5 w-% of bisphenol A and/or epoxy resins with respect to the entirecoating material, and is in particular bisphenol A free and/or epoxyfree. According to a further embodiment, the coating material comprisesone or more of a polyester resin, an acrylic resin, a fluorinecontaining resin (e.g. Lumiflon resin), and a di- or polyisocyanatecompound. According to a further embodiment, the coating materialcomprises a polyester resin with an acid value above 50, in particularabove 60, further in particular above 70, and/or an epoxy resin with anepoxy equivalent weight (EEW) of 300 to 700 g/eq, in particular 400 to600 g/eq and further in particular 500 to 560 g/eq, and/or anaccelerator (e.g. an accelerator as described herein).

According to a further embodiment, the coating material is configuredto, serve at least one of the following functions: forming a part of acoating layer representing an image, sealing, high-temperatureresistance, weathering resistance, long-term ultraviolet stability,wearing coat, being free from pinholes, wear based bleaching protection,outdoor capability, scratch resistance, resistance to solvents,diffusion reduction, corrosion protection, high temperature resistance.

According to a further embodiment, the amount of the amorphous resincomponent is at least 30 w-%, in particular 50 w-% and further inparticular at least 70 w-% with respect to the overall amount of resinin the coating material.

According to a further embodiment, there is provided a use of a coatingmaterial according to one or more embodiments of the herein disclosedsubject matter, for protection of substrates in particular againstcorrosion and/or weather and/or UV-light and/or aggressive liquidsand/or scratching; wherein the coating material is in particular appliedby NIP, wherein the coating material is in particular applied with aresolution higher than 100 DPI, further in particular with a resolutionhigher than 200 DPI and further in particular with a resolution higherthan 300 DPI, further in particular with a resolution of more than 2l/mm, in particular more than 5 l/mm and further in particular more than10 l/mm.

According to a further embodiment, there is provided a use of a coatingmaterial according to one or more embodiments of the herein disclosedsubject matter, for protection of substrates against corrosion and/orweather and/or UV-light and/or aggressive fluids (liquids and/or gases(such as ozone)) and/or scratching, in particular wherein the coatingmaterial is transparent and/or is applied via a NIP method.

Generally herein, according to an embodiment the use of a coatingmaterial may include a use of a developer comprising the coatingmaterial.

For example, according to a further embodiment, there is provided a useof a developer according to one or more embodiments of the hereindisclosed subject matter for generating from the coating material acoating layer for protection of substrates in particular againstcorrosion and/or weather and/or UV-light and/or aggressive liquidsand/or scratching; wherein the coating material is in particular appliedby non-impact printing; wherein the coating material is in particularapplied with a resolution higher than 100 DPI, further in particularwith a resolution higher than 200 DPI and further in particular with aresolution higher than 300 DPI, further in particular with a resolutionof more than 2 lines per millimeter, in particular more than 5 lines permillimeter and further in particular more than 10 lines per millimeter.According to a further embodiment, the coating material may not providefull protection of the substrate but rather adds to the protection ofthe substrate. According to a further embodiment the coating material isused to provide a decorating effect (e.g. an image) to the substrate.According to a further embodiment the coating material may provide bothprotection and a decorating effect (e.g. an image) to the substrate.

According to an embodiment, there is provided a use of a developeraccording to one or more embodiments of the herein disclosed subjectmatter for generating from the coating material a coating layer forprotection of substrates against corrosion and/or weather and/orUV-light and/or aggressive liquids and/or scratching, in particularwherein the coating material is transparent and/or applied via anon-impact printing method.

According to an embodiment, there is provided a method, the methodcomprising: applying a coating layer generated from the coating materialaccording to one or more embodiments of the herein disclosed subjectmatter (e.g. from the coating material of the developer according to oneor more embodiments of the herein disclosed subject matter) to a targetsurface, in particular by means of a NIP device.

According to an embodiment, the target surface is a surface of atransfer element which is used to transfer the coating layer to asubstrate. According to a further embodiment, the target surface is asurface of a substrate. According to a further embodiment, the methodfurther comprises: mixing at least one carrier (e.g. at least one solidcarrier or at least one liquid carrier) with the coating material.

According to an embodiment, there is provided a reservoir, in particulara cartridge, for a NIP device, the reservoir comprising a coatingmaterial according to one or more embodiments of the herein disclosedsubject matter.

According to an embodiment, there is provided a reservoir, in particulara cartridge, for a NIP device, the reservoir comprising a developeraccording to one or more embodiments of the herein disclosed subjectmatter.

According to an embodiment, there is provided a NIP device comprising acoating material according to one or more embodiments of the hereindisclosed subject matter.

According to an embodiment, there is provided a NIP device comprising adeveloper according to one or more embodiments of the herein disclosedsubject matter.

According to an embodiment, there is provided a transfer elementcomprising a coating layer generated from the coating material accordingto one or more embodiments of the herein disclosed subject matter.

According to an embodiment, there is provided a transfer elementcomprising a coating layer generated from a coating material of thedeveloper according to one or more embodiments of the herein disclosedsubject matter.

According to an embodiment, there is provided a substrate, in particulara pre-coated substrate, the substrate comprising a coating layergenerated from the coating material according to one or more embodimentsof the herein disclosed subject matter.

According to an embodiment, there is provided a substrate, in particulara pre-coated substrate, the substrate comprising a coating layergenerated from the coating material of the developer according to one ormore embodiments of the herein disclosed subject matter.

According to an embodiment, the coating layer in particular has athickness of at least 10 μm, in particular a thickness of at least 15 μmand further in particular a thickness of at least 30 μm.

According to an embodiment, the coating layer represents an image andwherein a resolution of the image is at least 100 DPI, in particular atleast 200 DPI and further in particular at least 300 DPI, further inparticular more than 2 l/mm, in particular more than 5 l/mm and furtherin particular more than 10 l/mm.

According to an embodiment, the (cured) coating layer on the substratehas an indentation hardness of above 87 with a layer thickness of 60μm-80 μm according to ISO 2815 is given.

According to an embodiment, the (cured) coating layer on the substratehas a minimum glass transition temperature above 50° C., 60° C., inparticular above 80° C.

According to an embodiment, the (cured) coating layer on the substratehas a remaining gloss after 300 hours of UV exposure according to GSBinternational AL631-PartVII-segment 20.1 Kurzbewitterung UV-B (313), isat least 50%.

According to an embodiment, the cured coating layer on the substrate hasa remaining gloss after 600 hours of UV exposure according to the testprocedure of GSB international AL631-PartVll-segment 20.1Kurzbewitterung UV-B (313) of least 50%, in particular at least 85%.

According to an embodiment, the (cured) coating layer on the substratehas a remaining gloss after 1000 hours of Xenon exposure according to ENISO 16474-2 determined according to ISO 2813, of at least 50%, inparticular at least 85%.

According to an embodiment, there is provided a coating layerapplication device, the coating layer application device beingconfigured for receiving a transfer element comprising a coating layergenerated from a coating material according to one or more embodimentsof the herein disclosed subject matter, the coating layer applicationdevice being further configured for applying the coating layer to asubstrate.

According to a further embodiment, there is provided a coating layerapplication device, the coating layer application device beingconfigured for receiving a transfer element comprising a coating layergenerated from the coating material of the developer according to one ormore embodiments of the herein disclosed subject matter, the coatinglayer application device being further configured for applying thecoating layer to a substrate.

According to an embodiment, a layer thickness is determined according toISO 2360. According to an embodiment, a reflectometry value isdetermined according to ISO 2813. According to an embodiment, a crosscutting/grid testing is performed according to ISO 2409. According to afurther embodiment, an indentation hardness is determined according toISO 2815.

According to an embodiment, a charge control agent is used. The chargecontrol agent is preferably salicylic acid or a derivative thereof, morepreferably zinc salicylic acid or a derivative thereof. By the presenceof the charge control agent, in particular salicylic acid or aderivative thereof, the stability of the coating material issignificantly enhanced in a particular when the coated substrate is usedin outdoor applications. An enhanced stability of the coating materialbecomes particularly significant when rather harsh environmentalconditions prevail or in the case of the coating material being exposedto mechanical stress.

Surprisingly, by using a charge control agent, which is preferablysalicylic acid or a derivative thereof, network build-up may be moreconsistent during the curing process. By such a more consistent networka particularly high resolution may be achieved with at the same timeequally and uniformly distributed color tones.

Surprisingly it was found that for high color density printing, bestcolor density was achieved with values of about 1 w-% of charge controlagent in the coating composition, in particular with values higher than1 w-%, preferably higher than 2 w-%.

Surprisingly, using a charge control agent with unevenly distributedparticle sizes is particularly effective for obtaining higher qualityprinting results.

In an embodiment, coatings comprising a suitable amount of chargecontrol agent may be only applied to areas which are particularlyexposed to mechanical stress. For instance by means of the describedprinting process, it is possible to selectively provide a coating onhandles, rails and tracks for example in machines or machine componentswhich are usually exposed to high mechanical stress. Surface coatingsfor a plurality of substrate structures in a variety of different fieldsof technology can therefore be provided efficiently.

In an embodiment, a suitable amount of the charge control agent is inparticular 1 to 5 w-%. By such an amount of the charge control agent, anoptimum of the relevant parameters, which are resistance to distortions,deformations and abrasion, due to harsh environment conditions and/ormechanical stress, on the one hand, and the high resolution, on theother hand, may be achieved. Stated differently, in particular byproviding a charge control agent in an amount of 1 to 5 w-% an optimalcomposition may be obtained for providing not only stability but alsohigh resolution for ensuring a high quantity and quality printingprocess.

Not being bound to any theory, it is assumed by the inventors that thesurface of the charge control agent particles, which have in particularspike-like structures on their surface, contributes to an inneradherence of the coating material by means of a indention process. Suchan internally indented coating material allows for the application ofsteeper angles and consequently to a better resolution of the finalcoating with well and clearly defined contours.

According to an particularly preferable example, the coating materialcomprises a charge control agent and a silica material, i.e. an oxide ofsilicon with the chemical formula SiO₂ or derivatives thereof, in anamount of 1 w-% to 5 w.-%. In the example, the charge control agent ispreferably salicylic acid or a derivative thereof and the particle sizeof the coating material is between 5 μm to 15 μm, the sphericity of thecoating particles is above 0.8. Further, in the example the silicamaterial has a diameter in a range of 1 nm to 50 nm. Further, in theexample preferably the diameter selection of the charge control agent isin a range of 1 μm to 20 μm.

According to an embodiment, a particle size distribution of the chargecontrol agent exhibits a d10 of between 0.5 μm and 5 μm, and/or a d90 ofbetween 5 μm and 50 μm. According to a further embodiment, the particlesize distribution of the charge control agent exhibits a d10 of between0.5 μm and 3 μm and/or a d90 of between 5 μm and 25 μm. According to afurther embodiment, the particle size distribution of the charge controlagent exhibits a d10 below 2 μm and/or a d90 below 10 μm.

According to an embodiment, the coating material is at least partlycurable, in particular by crosslinking. Reduction of a contact pressureapplied onto the coating material (coating layer) may be particularlyadvantageous for the coating as described in the present application,since a large contact pressure of a heating system may result indeformations and distortions of the printed image. Such deformations anddistortions of the printed image may dramatically deteriorate theresolution of the printed image and are to be avoided. Therefore, acoating material which is at least partly curable, in particularcomprising at least one component capable of forming crosslinks, ispreferable for achieving an improved resolution of the printed image.Correspondingly, the process of forming of the coating material on thesubstrate by the printing process as described in the herein disclosedsubject matter comprises in an embodiment a curing step, which can be anon-thermal curing step (e.g. a light induced curing step) or athermally induced curing step, by which the coating material, which isat least partly curable, is cured, in particular by the formation ofcrosslinks by at least one component capable of forming crosslinks.

According to a further embodiment, the non-impact printing device isconfigured for and may be used for generating a surface structure byapplying a plurality of coating layers, i.e. at least one second coatinglayer being placed on and/or adjacent to at least one first coatinglayer. The plurality of coating layers are applied subsequently.According to an embodiment, at least one of the coating layers of theplurality of coating layers is subjected to a pre-curing process,preferably by using a light source, preferably UV-light. By means ofapplying a plurality of coating layers in combination with at least onepre-curing step an improvement of the resolution can be achieved as thelayers can be applied in a controlled and precise manner.

Chapter 8

According to an embodiment, there is provided a coating materialconfigured for generating a coating layer by NIP, the coating materialcomprising: at least one effect particle, comprising at least one atleast partially covered effect pigment, the effect pigment beingcovered, at least partially, by a curable polymeric matrix.

According to an embodiment, the polymer matrix is transparent.

Further, according to an embodiment, the coating material is curable, inparticular thermally curable and/or radiation curable, further inparticular at least partially thermally curable and/or at leastpartially radiation curable.

Further, according to an embodiment, the curable polymer matrix isthermally curable and/or radiation curable. Further, according to anembodiment, the curable polymer matrix is at least partially thermallycurable and/or at least partially radiation curable.

According to a further embodiment, the coating material furthercomprises a curing agent, in particular a curing agent capable ofcross-linking with at least one component of the curable polymericmatrix.

According to an embodiment, the coating material is provided in the formof a plurality of particles and an average particle diameter of theplurality of particles being between 5 μm and 100 μm, in particularbetween 5 μm and 50 μm, further in particular between 7 μm and 60 μm,further in particular between 7 μm and 70 μm, further in particularbetween 7 μm and 20 μm, further in particular between 7 μm and 50 μm.

According to a further embodiment, the coating material comprises aresin, the resin comprising a curable resin component, wherein the atleast one effect particle is at least part of a first material portionof the coating material wherein the resin is part of a second materialportion of the coating material.

According to an embodiment, the curable resin component is at leastpartially thermally curable and/or is at least partially curable by acrosslinking agent able to react with functional groups of the resincomponent, further in particular wherein the resin comprises anamorphous resin portion.

According to an embodiment, the first material portion and the secondmaterial portion being mixed with each other. According to a furtherembodiment, the coating material comprises the first material portionand the second material portion at a mass ratio of 1% to 50% of thefirst material portion to 50% to 99% of the second material portion. Perdefinition, the percentage of the first material portion and thepercentage of second material portion add to 100%. For example, the massratio could be 10% of the first material portion to 90% of the secondmaterial portion.

According to an embodiment, the effect pigments are metallic effectpigments.

According to a further embodiment, the effect pigments are pearl lusterpigments and/or interference pigments.

According to an embodiment, the second and/or the first material portionfurther comprise a charge control agent and/or silica and/or titaniumdioxide wherein the silica and/or titanium dioxide have an averageparticle diameter of between 1 nm to 150 nm.

According to an embodiment, there is provided a method of producing acoating material according to one or more embodiments of the hereindisclosed subject matter, the method comprising: heating the curablepolymer matrix so as to soften the curable polymer matrix; and addingthe at least one effect pigment into the softened curable polymermatrix.

According to an embodiment, the at least one effect pigment is added tothe softened curable polymer matrix via at least one side feeder duringan extrusion process; and/or wherein an average diameter of the effectpigments after adding to the softened curable polymer matrix anddispersing the effect pigments therein is at least 80%, preferably atleast 90% of an average diameter of the effect pigments before theaddition to the softened curable polymer matrix. In accordance with anembodiment, the side feeder may be used for adding any kind of additiveto the coating material.

After covering the effect pigment with the curable polymer matrix (e.g.a transparent curable polymer matrix) in the extrusion process (i.e. inan extruder), the extrudate is broken, grinded (preferably jet milled)and/or classified to obtain the desired particle size distribution.

According to an embodiment, the effect particles are part of a coatingmaterial which is provided in a cartridge and is then printed bynon-impact printing. According to a further embodiment, any othercoating material (e.g. a colored coating material (e.g. CMYK)) islocated in a separate cartridge.

Accordingly, in an embodiment, the effect particles are part of a firstcoating material which does not contain a second material portion (e.g.a colored toner) but which is provided in a separate cartridge and isthen printed by non-impact printing. According to a further embodiment,any other coating material (e.g. a colored coating material (e.g. CMYK))is located in a separate cartridge. According to an embodiment, aprinting order is: the second (e.g. colored) coating material, then thefirst coating material (effect particles) on top or vice versa, oreffect particles somewhere in between two or more layers of a second(e.g. colored) coating material.

According to an embodiment, a set of coating materials is provided, eachcoating material of the set of coating materials being configured forgenerating a coating layer by non-impact printing, the set of coatingmaterials comprising (at least): a first coating material comprising atleast one effect particle, comprising at least one at least partiallycovered effect pigment, the effect pigment being covered, at leastpartially, by a curable polymeric matrix, wherein the polymer matrix ispreferably transparent; a second coating material comprising a resin,the resin comprising a curable resin component, in particular whereinthe curable resin component is at least partially thermally curableand/or at least partially radiation curable and/or is at least partiallycurable by a crosslinking agent able to react with functional groups ofthe resin component, further in particular wherein the resin comprisesan amorphous resin portion.

According to an embodiment, the first coating material and the secondcoating material are compatible with each other (e.g. regarding printingand/or curing) such that they can be printed in direct contact with eachother. Hence, according to an embodiment, in a layer package a firstcoating layer generated from the first coating material and a secondcoating layer generated from the second coating material are contactingeach other. According to an embodiment, the set of coating materialscomprises one or more first coating materials and one or more secondcoating materials. For example, in an embodiment four second coatingmaterials are provided, such as a CYMK system. According to anembodiment, the compatibility is achieved because functional groups ofthe first coating material can react with functional groups of thesecond coating material upon curing.

According to an embodiment, the second coating material may beconfigured as the second material portion described herein. According toa further embodiment, the second coating material may be configuredaccording to any one or more embodiments of a coating material describedherein.

According to an embodiment, a 2K system (effect particles+carrier) maybe provided, in accordance with embodiments of the herein disclosedsubject matter. According to an embodiment, the final layer (e.g. with atransparent channel) can be achieved by the transparent matrix of theeffect pigment.

According to an embodiment, the method further comprises forming aplurality of the effect particles from the curable polymer matrix withthe added at least one effect pigment. According to a furtherembodiment, the method further comprises an after treatment of theeffect particles so as to improve a coverage of the effect pigments withthe curable polymer matrix, in particular by initiating viscous flow ofthe polymer matrix and/or by additional coating.

According to an embodiment, the method further comprises adding thesecond material portion to the first material portion. According to afurther embodiment, the method further comprises at least partiallycuring the curable polymeric matrix before adding the second materialportion to the first material portion.

According to an embodiment, the method comprises mixing the secondmaterial portion and the first material portion, in particular such thatan average particle size of the effect particles after the mixing is ina range of 70% to 100%, in particular in a range of 80% to 90% of anaverage particle size of the effect particles before the mixing. Amoderate reduction of the average particle size due to mixing may beachieved by choosing suitable mixing parameters so as to achieve gentlemixing.

According to an embodiment, there is provided a coating layer, inparticular a coating layer generated from a coating material accordingto one or more embodiments of the herein disclosed subject matter,wherein the coating material comprises at least one effect particle.According to a further embodiment, there is provided a coating layergenerated according to a method of producing a coating materialaccording to embodiments of the herein disclosed subject matter.

According to an embodiment, at least one channel formed from the curablepolymer matrix extends between a surface of the coating and an effectpigment out of the at least one effect pigment, in particular whereinthe curable polymeric matrix is transparent. According to an embodiment,the curable polymeric matrix of the at least one channel is transparent.

According to an embodiment, there is provided a substrate comprising alayer package comprising at least one layer, wherein at least one of theat least one layer is a coating layer which comprises at least oneeffect particle, in particular wherein the coating layer is cured.

According to an embodiment, there is provided a transfer elementcomprising a layer package comprising at least one layer, wherein atleast one of the at least one layer is a coating layer (according to oneor more embodiments) comprising at least one effect particle. Accordingto an embodiment, the coating layer on the transfer element may bepartially cured or has been subjected to viscous flow.

According to an embodiment, there is provided a use of a coatingmaterial comprising at least one effect particle for NIP of a coatinglayer.

According to an embodiment, there is provided a use of a coatingmaterial comprising at least one effect particle, in particular fordirect NIP of the coating layer onto a substrate, in particular onto aprecoated substrate. According to a further embodiment, there isprovided a use of a coating material comprising at least one effectparticle for indirect NIP of the coating layer onto a transfer elementwhich is configured for transferring the coating layer to a substrate,in particular a precoated substrate.

According to an embodiment, there is provided a processing deviceconfigured for processing a coating material according to one or moreembodiments of the herein disclosed subject matter, the processingdevice comprising in particular at least one of: a NIP device configuredfor printing the coating material to thereby generate a coating layer; apretreatment device configured for treating the coating layer beforeapplication of the coating layer to a substrate; a coating layerapplication device for applying the coating layer, printed onto atransfer element, from the transfer element to the substrate; a curingdevice for curing the coating layer applied to the substrate; whereinone or more of the NIP device, the pretreatment device, the coatinglayer application device, and the curing device are located at the samelocation and/or one or more of the NIP device, the pretreatment device,the coating layer application device, and the curing device are locatedin different locations.

According to an embodiment, there is provided a method of processing acoating material according to one or more embodiments of the hereindisclosed subject matter, the method including in particular at leastone of: printing the coating material to thereby generate a coatinglayer; treating the coating layer before application of the coatinglayer to a substrate; applying the coating layer, printed onto atransfer element, from the transfer element to the substrate; curing thecoating layer applied to the substrate.

According to an embodiment, there is provided a reservoir, in particulara cartridge, for a NIP device, the reservoir comprising a coatingmaterial according to one or more embodiments of the herein disclosedsubject matter.

A coating material according to embodiments of the herein disclosedsubject matter may be provided for electrophotography and hence may bereferred to as a toner (although being different from conventionaltoners). Further, although some embodiment refer to a toner, theseembodiments are as well applicable to a coating material according tothe herein disclosed subject matter in general.

Embodiments relate to an effect toner characterized by at least oneeffect particle, where the at least one effect particle is covered atleast partially by a curable polymeric matrix A, preferably thepolymeric matrix A being transparent. In particular the toner isincluding a curing agent which can crosslink with at least one componentof the transparent polymeric A matrix and/or the toner has an averageparticle diameter between 5-100 μm, in particular between 5 and 50 μm,in particular between 7 and 20 μm. An embodiment relates to a tonercomprising at least one base toner B and at least one effect toner Ahaving effect pigments, the production of an effect toner of this typeby means of an effect pigment-preserving dispersion of effect pigmentsin a melt of transparent toner, for example by means of gentleextrusion, and an effect coating as can be provided by the toneraccording to embodiments of the herein disclosed subject matter.

Toners with metallic effects are not very broadly used as they aredifficult to produce and use based on the fact that the effect pigmentsoften are conductive and therefor the charging properties in theprinting machine are negatively influenced.

The following documents describe aspects of conventional toners: U.S.Pat. No. 9,383,669B2; WO2013166139A1; US20160216623A1; U.S. Pat. No.9,323,169B2.

However, up to now no industrial effect toner printing solution is knownwhich can be used to cover the needs of high quality printing togetherwith a printing that can withstand the harsh environmental conditions ofindustrial applications. These conditions can include:

1) High weather resistance/high UV resistance

2) Resistance against abrasion

3) High chemical stability

4) Mechanical strength and/or flexibility

5) Adhesion to industrial substrates like steel, glass, ceramic, wood,MDF or plastics

Embodiments of the herein disclosed subject matter enable to fulfil oneor more of these conditions.

Effect toners for use in the printing field should be characterized by apronounced effect (what is referred to as a sparkling effect) that isparticularly effective especially for dark basic color tones. Due to thehigh contrast between lighter, brilliant effect pigments and the darkbasic color, the slightest differences in the effect concentration,above all on the finished object, are very easy to recognize,particularly if printing is to take place on larger areas and multipleprinted sections were aligned in an end-to-end manner. In addition, forthe use of metallic pigments or powders which contain the metallicpigments, closer attention must be paid to the explosion protectionduring handling.

Current known metallic toner systems do not sufficiently fulfill theserequirements and therefor the market requires a solution which can closethis gap.

It was surprisingly found that toners for industrial applications withmetallic effects can be achieved with the coating material according toembodiments of the herein disclosed subject matter. Embodiments of thistoner systems can be even used for architectural applications withsuitable resin systems as described below. However, for someapplications an additional top coat might therefor be suggested. Apreferred embodiment is given where the material comprises effectpigments with a diameter of less than 50 μm, preferably less than 20 μmand most preferably less than 10 μm. This effect pigments can be chosenout of the known state of the art. A special embodiment of ametallic/effect toner according to embodiments is given when more than50%, preferably more than 75% and most preferably more than 90% of thesurface of the effect pigment is covered with a curable material whichis not electrically conductive or at least has a high ohmic resistancecompared to metallic effect pigments. This curable material includes inparticular a curing agent to react with a resin and/or is preferably atleast partly transparent. Here surprisingly very good properties in theprinting stability and printing quality as well as the effect qualityand also durability against the environment was given. Such a matrix canalso be curable via radiation like UV-light or electron beam. However,for many industrial applications the curing of a printing purely viaradiation limits the potential applications dramatically based on thefact that big and complex substrates have to be printed and theaccessibility of radiation is therefore limited, especially with thecurrent designs of industrial ovens in the market.

The presented embodiments herein provide a solution to cover theseneeds. The present embodiments furthermore provide a cost efficientmethod to produce such a toner material with sparkling effects.

Surprisingly it was found that effect toner with good printingproperties can be produced when the effect pigments are at least partlycoated with an at least partly transparent coating. This coated pigmentscan then be mixed with a colored toner matrix (e.g. by dry blending orany other suitable method) and give brilliant colored toners withmetallic effects. Furthermore, even more surprisingly it was found thatthe coating can withstand industrial applications when the at leastpartly transparent coating is curable and furthermore the colored tonermatrix is also curable. Most preferably the curable matrix of the toneras well the curable transparent coating on the effect pigments isthermally curable, especially with a curing agent. Surprisingly it wasfound that if the formulations based on powder coatings are adjusted totoner applications (e.g. by adding a charge control agent and/or silica)suitable charging properties of metallic toners with the excellentproperties of powder coatings for industrial applications can be merged.

Surprisingly it was found that by the use of a curable transparentcoating on the effect pigments transparent channels can be built from aneffect pigment up to the surface of the final cured printed layer whichlead to an increased metallic effect of the printing.

Surprisingly it was found that the effect pigment leads to very goodeffects when the effect pigment was covered with the preferably at leastpartly transparent matrix by mixing the effect pigment and thepreferably at least partly transparent matrix by extrusion, especiallywhen a side-feeder was used to add the effect pigments to the at leastpartly transparent matrix and the side feeder allows adding the effectpigments with low shear forces.

An object may be considered as the production of unique and brillianteffect toners for use in the printing field, including electrostatic,electrophotographic and 3D printing, wherein the appearance and/oreffect manifestation of the effect toner according to the embodiments isnot influenced or only insignificantly influenced by the printingprocess. These absolutely process-reliable and pronounced metalliceffects have a special impression of depth and are even suitable in anembodiment for use in highly weather-resistant systems. Furthermore, thepresent embodiment relates to a toner of this type, containing effectpigments produced according to the embodiments in a ground premix.

Surprisingly, it was found that the combination of a ground premix,comprising effect pigments dispersed in a melt of at least onetransparent curable matrix, with an additional toner forming the base ofthe effect toner keeps the shear forces occurring on the effect pigmentso low that the majority of the effect pigments do not experience anysignificant reduction in particle size. Equally surprisingly, it wasfound that the at least partial envelopment of the metallic pigmentswith a transparent curable matrix significantly reduces the negativeeffects of the conductive pigments on the charge behavior of the tonerduring the printing process.

Particularly surprisingly, it was found in an embodiment that thecombination of metallic pigments in an at least thermally curable matrixwith a base toner is suitable for producing weather-resistant coatingsin a printing process, and that the toner and matrix satisfy thecorresponding requirements for UV and weather resistance according toindustrial standards (e.g., AAMA, GSB, etc.). In this case, it ispossible, with the use of toner formulations that are based on powdercoatings (e.g. by adding charge control agents and/or silica), tocombine the charge characteristics of toners with the coatingcharacteristics of industrial powder coatings.

Effect toners of this type are characterized by at least one of thefollowing points:

-   -   High process stability under a wide range of different printing        parameters    -   Pronounced metallic effects, in particular characterized by a        high impression of depth, a brilliant effect and specifically by        an independence from the viewing angle of the effects.        Additionally, substrates printed with the metallic toners        according to embodiments show significantly fewer color        fluctuations over the area.    -   Improved printing properties, since the at least partial        envelopment of the metallic pigments with a preferably        transparent curable matrix improves the charge behavior of the        metallic toner during the printing process.    -   High weather resistance/high UV resistance    -   Resistance against abrasion    -   High chemical stability    -   Mechanical strength and/or flexibility    -   Adhesion to industrial substrates like steel, glass, ceramic,        wood, MDF or plastics

According to an embodiment, the object mentioned above is attained by atoner comprising at least one base toner B and at least one effect tonerA having effect pigments, wherein the effect pigments in effect toner Aare at least partially enveloped by an at least partially transparentcurable toner matrix. The effect pigments can thereby be dispersed in amelt of at least partially transparent and mostly colorless tonermatrix. A toner composition that is mainly only composed of resins andcuring agents and/or initiators (like UV and/or thermal initiators)and/or curing catalysts and necessary additives (e.g. for setting thechargeability) is typically used as a transparent and mostly colorlessmatrix. The hardened matrix shows a high transparency. Within the scopeof embodiments, a transparent matrix is preferably used which, athardened film layer thicknesses of 15 μm, still has sufficienttransparency to detect the coating layers or substrates locatedtherebelow.

The effect pigment can be incorporated in the binder matrix of toner Aby many different ways. For example extrusion is a possibility. Aspecial embodiment is shown afterwards:

An excessively strong shear stress during the dispersion (mixing orextrusion) of effect pigments in a toner produced in this mannertypically causes the effect pigments to become damaged, and to no longerachieve the desired effect or to achieve at least a strongly reducedeffect. Furthermore, other disadvantages also result, such as the poorerprocess characteristics mentioned above. Surprisingly, it was shown thatthe low-shear introduction of effect pigments into molten transparenthardenable toners enables a very suitable dispersion/homogenization ofthe effect pigments in the polymer matrix of the transparent toner.

Particularly surprising in this case was the finding that, quite thecontrary, with a toner containing at least two toners A and B, whereintoner A contains effect pigments that are at least partially surroundedby an at least partially transparent toner matrix, and toner B is acolored base toner and is not transparent as described herein,outstanding effect characteristics occurred, such as a uniform color andeffect impression of printed substrates (with none of what is referredto as clouding), and above all an effect appearance that is essentiallyindependent of the viewing angle.

In the opinion of the inventors—without being bound to a theory—theobserved and measured effect can be explained in that, with the toneraccording to embodiments, channels form in the toner layer which arecomposed of transparent toner. Thus, even those pigments that are not onthe surface, but rather only in the interior of the coating can becomevisible for the observer. This effect results on the one hand in theindependence from the viewing angle, but also in an opticallyperceptible 3D effect or an impression of depth of the toner accordingto embodiments.

In one embodiment of the toner, the shear forces occurring on the effectpigment in effect toner A during production are so small that themajority of the effect pigments do not experience any significantreduction in particle size. This can be technically attained in that,for example, transparent toner is melted or at least softened in aheated stirred reactor, for example, and at least one effect pigment isstirred into the softened polymer matrix (e.g. a melt), wherein theeffect toner A produced from this mixture by means of grinding after thecooling is then mixed with an opaque, preferably colored base toner B.Other technical embodiments are also conceivable within the scope ofembodiments. One preferred embodiment consists in that at least oneeffect pigment is added to the transparent softend polymer matrix (e.g.the toner melt) via at least one side feeder during an extrusionprocess, wherein the effect toner A (effect particles/first materialportion) produced from this polymer matrix (e.g. the toner melt)comprising the at least one effect pigment by grinding after the coolingis subsequently mixed with a base toner B (second material portion),thereby resulting in a coating material which can be used in accordancewith embodiments of the herein disclosed subject matter. The term “sidefeeder” implies the addition of a substance (typically an additive oreffect pigment according to the prior art, see for example informationmaterial from the extruder manufacturer Leistritz Extrusionstechnik GmbH(Germany) “Master_V_07_GB/17.09.13 Masterbatch”) at a different positionin the extruder processing section than directly at the beginning of theextruder (premix feed in barrel 1). By means of the side feeder, theeffect pigment is force-fed laterally into the extruder and introducedinto the softened polymer matrix (e.g. melt) at a defined ratio to thetransparent toner premix. The shear force that acts on the pigment inthe extruder can be influenced by the position of the side feeder alongthe processing section and the screw configuration used. A low shearforce within the extruder is characterized by a low destruction of theeffect pigment. Through the use of screw elements that are only used formixing or for conveying the extruder melt, a reduction of the shearforces to an amount provided according to embodiments with asimultaneous sufficient homogenization/dispersion is possible. Aboveall, an addition in the rear section, preferably in the final third ofthe processing section (e.g. in the second-to-last housing) of theextruder via a side feeder has proven particularly advantageous.Starting from the adding point of the pigment, the shear force is keptas small as possible by special screw configurations, for example theexclusive use of conveying elements, so that the pigment(s) is/are onlydestroyed or damaged to a small extent.

As previously mentioned, a transparent effect toner A can be producedfor the toner according to embodiments by adding at least one effectpigment by means of at least one side feeder into the softened polymermatrix (e.g. melt) of a subsequently transparently hardening tonerduring an extrusion process and by grinding the cooled polymer matrix(cooled melt), wherein effect toner A is then mixed with at least oneadditional toner B according to embodiments as disclosed herein,referred to as the base toner, for example by means of dry blending oranother suitable method. Also possible is the joint grinding ofextrudate chips from the effect toner A according to embodiments withextrudate chips of another toner B in a combined grinding process. Thebase toner B can thereby be a unicolored toner that does not contain anyeffect pigments, or an effect-containing toner.

As previously mentioned above, effect toner A can be produced in anextruder by adding effect pigments to an at least partially transparent,softened toner material (e.g. to an at least partially transparent tonermelt) via a side feeder. The side feeder itself is located in the finalthird of the processing section. After the adding point of the sidefeeder, only small shear forces are introduced via the extruder shaft.After the extruding, the effect toner is cold-rolled, broken down,ground and classified. The toner according to embodiments can beproduced by preparing and weighing the raw materials, including thetransparent effect toner A and the base toner B, subsequent premixing,extrusion or mixing, cold rolling, breaking down, grinding andclassifying.

In a preferred embodiment of the present invention, the toner accordingto embodiments comprises effect toner A mixed with base toner B at amass ratio of 1%-50% effect toner A to 50%-99% base toner B, inparticular preferably 5%-30% effect toner A to 70% to 95% base toner B.The production of the toner according to embodiments can take place bymeans of what is referred to as dry blending. The mixing of effect tonerA with base toner B in the softened (or melt) phase or other suitablemethods is also possible within the scope of embodiments.

As extruders, generally all types available on the market, such assingle- or double-shaft extruders, can be used with a side feeder withinthe scope of embodiments. The parameters that are to be set for thispurpose, such as screw configurations, torque and throughput, can bedesigned flexibly depending on the toner system used and the tonerproperties that are to be set, provided that the shear forces are keptappropriately low starting from the adding position of the effectpigments via the side feeder. Here, a positioning of the side feeder foradmixing effect pigments in the rear third of the extruder with thetested extruder types commercially available on the market has provensuccessful. To ensure clarity in this regard, it should be noted that itis, of course, also possible to supply materials other than effectpigments to the toner via the side feeder(s) (for example, additives).

Other embodiments that also enable an admixture into the softenedpolymer matrix (or into the melt phase) without significant shear forcesare naturally also within the scope of embodiments.

This method has proven particularly successful for the toner productionaccording to embodiments of toners which exhibit a very clearly visiblesparkle effect. An effect of this type can be produced in particular bymixing aluminum effect pigments with a D50>=35 μm in the shape of whatare referred to as silver dollars with a dark basic color hue. Silverdollar pigments are produced from a special aluminum grit and groundaccording to the size classification. In this manner, pigments areformed which are characterized by their round to oval shape and smoothsurface. These pigments normally exhibit a very high degree ofsparkling, that is, light is hardly scattered and is more stronglyreflected by the pigment. The higher the contrast between effect pigment(light, silver) and basic color hue, the more difficult it is to producethese effect colors and process them at the end user. However, havingsaid this furthermore it should be mentioned that depending on theprinting device, the necessary resolution of the final printing otherembodiments with different particle size (e.g. smaller for highresolution prints, bigger for prints with high haptic effects) are alsoin the scope of embodiments.

Specific substrates for coating with the toners (coating materials)according to embodiments are in particular pretreated and/orcleaned/degreased aluminum alloys, or steel and alloys thereof. Othersuitable industrial substrates without limitations could be MDF, wood,particle boards, glass, ceramic or polymers.

Coating Material/Toner:

Potential binding agents for the toners according to embodiments includesaturated and unsaturated systems. The latter can be, among otherthings, radically crosslinked by UV and/or thermal initiators such asperoxides.

Among these binding agents, specifically saturated polyesters play thelargest role. Carboxyl-functional polyester resins which have afunctionality of 2 or higher are named here by way of example. These canbe crosslinked with organic compounds that are capable of reacting withthe functional groups like carboxyl or OH groups of the polyester whileproducing a covalent bond, and if necessary, common pigments, fillersand additives can be added thereto. However, surprisingly it was foundthat without fillers and additives (especially flow additives) sometimeseven better printing performance was given. In the following descriptionis added for some potential embodiments without limitation according toembodiments.

Another embodiment includes an additional step of after treatment of thetoner particle which are at least partly covered by a curable,preferably transparent, polymer matrix. This step is done to reduce orcompletely prevent surfaces of the effect pigments which are not coveredby the curable, preferably transparent, polymer matrix. This steps canbe for example thermal treatment to allow viscous flow of the polymermatrix over the uncovered surfaces and/or additional coating afterwardse.g. via spraying (maybe liquids or even gas- or vapor- orchemical-deposition).

In an embodiment the curable polymer matrix of which at least partiallycovers the effect pigments the matrix can be at least partially cured toreduce further flow of the matrix afterwards during processing, coatingand/or curing,

As hardeners for carboxyl-functional polyester resins, both triglycidylisocyanurate (=TGIC) and also the common alternatives such as, amongothers, ß-hydroxyalkylamides like PrimidR XL-552(=bis[N,N′-di-(β-hydroxyethyl)]-adipamide) or PrimidR QM-1260(=bis[N,N′-di-(β-hydroxypropyl)]-adipamide), both EMS chemicals, aresuitable for the production of weather-resistant coatings. A specialfeature of these (Primid) hardeners is their toxicological harmlessnessaccording to the current body of knowledge.

Other possible alternatives like TGIC as a hardener forcarboxyl-functional polyester resins are, for example, the glycidylesters of aromatic or cycloaliphatic dicarboxylic acids; an appropriatecommercially available hardener of an analogous chemical structure is,for example, AralditR PT 910 (terephthalic acid diglycidylester/trimellitic acid triglycidyl ester, approximately 75:25) from CIBASpezialitatenchemie GmbH. The presence of the trifunctional trimelliticacid ester in AralditR PT 910 can be considered advantageous for thecrosslinking density of cured coatings in comparison with purediglycidyl esters. However, other hardeners for carboxyl-functionalpolyester resins as known in the art are also within the scope of theherein disclosed subject matter.

Polyester resins for the production of weather-resistant powder coatingsthat are hardened with polyepoxides and/or β-hydroxyalkylamides haveamong other things typically an acid number in the range from 15 to 70mg KOH/g polyester and a hydroxyl number less than or equal to 10 mgKOH/g polyester. These are essentially composed of units of aromaticdicarboxylic acids, such as terephthalic acid and isophthalic acid, inaddition to which possibly smaller amounts of aliphatic and/orcycloaliphatic dicarboxylic acids, such as adipic acid and/orcyclohexane dicarboxylic acid, are used, and aliphatic diols, namelypreferably branched aliphatic diols, such as neopentyl glycol, inaddition to smaller amounts of linear and/or cycloaliphatic diols. Theadditional use of hydroxycarboxylic acids or functional derivativesthereof, such as the inner esters thereof (=lactones), is also possible.The modification of this type of resins through the use of dimeric andtrimeric aliphatic acids is also known. In addition, smaller amounts oftrifunctional or polyfunctional and possibly monofunctional compoundscan be used.

Other potential curable toner binder materials are epoxy, hybrid(combination of two or more different binder systems, for example thisterm is used for the combination of epoxy resins and polyester resinswhich often can react with each other, so therefore the epoxy is actinglike a crosslinker for the polyester), urethane or urethane buildingsystems and acrylate are just mentioned as additional options accordingto embodiments which can be used.

In a special embodiment so called leafing pigments and/or small effectpigments preferably with an average particle size between 1-20 μm, morepreferably between 2 and 10 μm are used to be mixed in a matrix whichcomprises at least one curable resin, in particular a transparent resinto provide a toner. This toner material can be printed and afterwardscan be coated by an additional at least partly transparent top coat,whereby this top coat can be applied by NIP (in particular by digitalprinting) or either by conventional coating means as liquid coatingand/or powder coating.

Effect Pigments for Toner:

For the toner according to embodiments, mainly two types of pigment areused as effect pigment, namely aluminum pigments and mica pigments.Brass pigments and copper pigments can also be used. However, also othereffect pigments are contemplated.

Effect pigments can be categorized into metallic effect pigments andspecial effect pigments.

For metallic effect pigments, platelets of metal, in particular ofaluminum, are used. Light is reflected by the metallic surface, which isperceived by the viewer as a metallic effect.

Important metallic effect pigments are aluminum, bronze and copperplatelets. Pearl luster pigments and interference pigments are groupedtogether under the term special effect pigments. Pear luster pigmentsare effect pigments which are composed of transparent platelets with ahigh refractive index. They create a pearl-like effect through multiplereflections. Interference pigments are effect pigments whose coloringeffect depends entirely or mostly on interference. Interference pigmentscan be based on transparent or non-transparent platelets. Most commonlyused in industry are metal oxide-coated mica pigments which, dependingon the type and thickness of the coating, can belong to the pearl lusterpigments or to the interference pigments. The most importantinterference pigments are platelet/flacky-shaped titanium dioxide,platelet/flacky-shaped organic pigments, metal oxide mica pigments,aluminum oxide flakes, Ca Al borosilicate flakes, silicon dioxideflakes, metal oxide-coated metal platelets or multilayer pigment. Manyof these pigments are also subsequently coated with metal oxides (forexample, titanium dioxide). The color effect can thus be influenceddepending on the oxide layer thickness. Commercial names therefor areIriodin®, Miraval® or Colorstream®.

Pigments based on natural mica are usually produced from naturallyoccurring muscovite mica by means of grinding, fractionating, cleaningand recoating, drying and calcination.

The effect of the pigments is based on the principle of directedreflection for metallic effect pigments, and directed reflection andinterference for pearl luster pigments.

A commonality between all effect pigments is that the effect is veryhighly dependent on the viewing angle. In visual comparisons, this issimulated by tilting the samples. A color measurement is only usefulwith multi-angle measuring devices.

In a preferred embodiment of the herein disclosed subject matter, it isprovided that, for the toner according to embodiments, the averagediameter of the dispersed effect pigments is at least 90% of the averagediameter of the original effect pigments. The diameter of the effectpigments (normally in the shape of pigment platelets) is, depending onthe type, typically approximately 3 to 100 μm; the thickness of theindividual platelets is less than 1 μm. The platelets can thereby becomposed of one or more layers. The substrate is thereby crystalline(for example, mica) or amorphous (glass platelets or silicon dioxideplatelets). To achieve a suitable effect appearance, the particles musthave a smoothest possible surface and must be aligned in the individualapplication.

The metallic effect pigments are also categorized into leafing ornon-leafing pigments.

Leafing pigments are aligned on the surface by means of special surfacetreatments in the hardened coating film. In this manner, a strongmetallic luster is produced. However, this effect is not scratch- orsmear-proof, which usually necessitates an overcoating with a protectiveclear coat film which of course can be provided by printing orconventional coating means.

Non-leafing pigments disperse uniformly in the film matrix afterapplication. Only a portion of the pigment is aligned on the surface. Asa result, they are protected against abrasion and chemical attack.However, the effect has a less brilliant and metallic appearance than isthe case with leafing pigments. Embodiments of the herein disclosedsubject matter will now be explained in greater detail using theexamples and figures below, wherein embodiments are not limited to theseexamples.

EXAMPLES

The toner according to this invention embodiments can be made from twocomponents where the one component (first material portion) is atransparent effect toner A and the other component (second materialportion) is the colored opaque base toner B. In order to produce thefollowing toner examples, all components were premixed in a high-speedmixer for 1 min, followed by extrusion in a twin-screw ZSK-18 extruder(temperature of the extruder segments: 60° C., 80° C., 100° C., 100° C.,about 30% of torque). The extruded compound was cooled down, granulatedand finely ground to produce a powder with the desired grain sizedistribution. The preferred grinding and classification was done byjet-milling with a Multino M/S/N opposed jet mill from NOLL if notstated otherwise with nitrogen inertisation. Before printing, silica(0.5% HDK H05 TD+1% HDK H30™ from Wacker Silicones) was bonded to thepowders using a Henschel Mixer MB10.

EXAMPLE

A transparent and colorless toner (effect toner) was made from 810 partsCrylcoat® 4642-3 or comparable polyester, 61 parts Primid® XL-552, 5parts Richfos® 626, 8 parts Benzoin, 2 parts Tinuvin® (Tinuvin® 144) and18 parts of CCA by mixing these components. By gravimetrical dosing thebefore mentioned mixture was fed to the extruder and molten anddispersed by the use of a suitable screw configuration which are knownby a person skilled to the art. In the last third of the extruder 5parts of aluminium powder PCU 5000 was fed via side feeder. Thetemperature inside the extruder is preferably hold below 120° C. Afterthe extrusion the molten extrudate was cooled down, broken and thengrinded down to a D50 of about 10 μm to 20 μm depending on the wantedeffect.

The particle size of the pigments (D50 or average particle size) isdepending on the desired effect and can be between 3 to 130 μm. Theeffect pigment concentration in the transparent masterbatch (toner A)can be between 1 w-% to 40 w-%, in particular between 2 w-% and 10 w-%.

The opaque and colored base toner B can be produced in a similar waythan described for the effect toner A. In particular the base toner Bincludes additionally color pigments but no more effect pigments.

One example for that kind of toner B is given here:

830 parts CRYLCOAT® 4655-2, 63 parts Primid® XL-552, 9 parts Benzoin and18 parts of CCA. For different colours (Cyan, Magenta, Yellow, Black andWhite) 32 parts of Heliogen Blue K7090 (BASF) for cyan, 32 parts ofCinquasia Violet L5120 (BASF) for magenta, 100 parts of Sicopal YellowL1100 (BASF) for yellow, 32 parts of Printex 90 BEADS (Orion EngineeredCarbons) for black or 190 parts of TI Select TS6200 (DuPont) for whitewere added.

After this both grinded toners A and B were mixed by dry blending in aratio A/B=20/80 according to the weight.

Further General Remarks

A combination of the technological fields of non-impact printing andpowder compositions is achieved by the herein disclosed subject matterand in particular by the claimed subject-matter. In this context itshould be noted that common coating powder compositions as used forpowder coating in industrial applications are not suitable fornon-impact printing. It has been found that this is in particular due tothe triboelectrical charging behavior of the commonly used powdercompositions.

Therefore, it is an object of the claimed subject matter toadvantageously combine both, the concept of non-impact printing as wellas the concept of coating powders profiting from the advantages of bothtechnical fields while at the same time avoiding the respectivedisadvantages.

It is a further advantage of the described technology, that therebyprinting becomes possible on surfaces which are not susceptible to thecommon direct printing methods. An Example for such a surface is forinstance a tin can for food conservation. Most cans are right circularcylinders with identical and parallel round tops and bottoms withvertical sides. However, where the small volume to be contained and/orthe shape of the contents suggests it, the top and bottom may berounded-corner rectangles or ovals. Even such surfaces as that of a tincan becomes available as possible printing targets of the presentlydescribed technology.

The aspects and embodiments defined above and further aspects andembodiments of the herein disclosed subject matter are apparent from theexamples to be described hereinafter and are explained with reference tothe drawings, but to which the invention is not limited. Theaforementioned definitions and comments are in particular also valid forthe following detailed description and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows the behavior of a glass-forming material withregard to temperature.

FIG. 2 schematically shows a simplified TTT diagram 100 indicating thetransformation of a thermosetting polymeric material.

FIG. 3 shows a cross-sectional view of a coating layer applicationdevice 200 according to embodiments of the herein disclosed subjectmatter.

FIG. 4 shows a coating layer application device according to embodimentsof the herein disclosed subject matter.

FIG. 5 to FIG. 8 illustrates different stages of a printing methodaccording to embodiments of the herein disclosed subject matter.

FIG. 9 illustrates a part of a coating layer according to embodiments ofthe herein disclosed subject matter.

FIG. 10 shows a printing device according to embodiments of the hereindisclosed subject matter.

FIG. 11 shows a further printing device according to embodiments of theherein disclosed subject matter.

FIG. 12 shows a part of a coating layer according to embodiments of theherein disclosed subject matter.

FIG. 13 shows results of adding silica in combination with differentparticle size distributions (PSDs) to a coating material according toembodiments of the herein disclosed subject matter.

FIG. 14. shows an exemplary DSC scan of a coating material according toembodiments of the herein disclosed subject matter.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The illustration in the drawings is schematic. It is noted that indifferent figures, similar or identical elements are provided with thesame reference signs. Accordingly, the description of the similar oridentical features is not repeated in the description of subsequentfigures in order to avoid unnecessary repetitions. Rather, it should beunderstood that the description of these features in the precedingfigures is also valid for the subsequent figures unless explicitly notedotherwise.

In the following, exemplary embodiments of the herein disclosed subjectmatter are described, any number and any combination of which may berealized in an implementation of aspects of the herein disclosed subjectmatter.

It is noted that as far as the embodiments and examples described belowrefer to a parameter range of a parameter (e.g. concentration, e.g. of aresin, temperature, etc.) which differ from parameter ranges specifiedabove for the parameter, according to an embodiment any parameter rangespecified below shall be replaced by a parameter range specified above.In other words, any statement (e.g. regarding effect, relationship,advantage etc.) specified below for a particular parameter range of aparameter is also valid for a respective parameter range specified abovefor the parameter, and vice versa. The same is true for types ofparameters. For example, statements given below regarding a firsttemperature are also valid for the first temperature range specifiedabove.

NIP or digital printing is gaining importance as the printing marketrequests more and more flexibility. The future goal is to be able toprovide a one piece printing at suitable prices which can only befulfilled by digital printing. Toners for digital printing are wellknown. However, up to now no industrial digital printing solution isknown which can be used to cover the needs of high quality printingtogether with a printing that can withstand the harsh environmentalconditions of industrial applications. These conditions can include:

1) High weather resistance/high UV resistance

2) Resistance against abrasion

3) High chemical stability

4) Mechanical strength and/or flexibility

5) Adhesion to industrial substrates like metal (e.g. aluminum, steel,etc.), glass, ceramic, wood, MDF or plastics

Known toner systems which can be cured by UV radiation might fulfillprincipally some of these requirements. However, for real industrialapplications the curing of a printing only with radiation limits thepotential applications dramatically based on the fact that big andcomplex substrates have to be printed and the accessibility of radiationis therefore limited, especially with the current designs of industrialfurnaces in the market. The market requires a solution which can closethis gap.

Embodiments of the herein disclosed subject matter are based on the ideathat surprisingly it is possible to use compositions which are based onthe chemistry used in powder coatings and therefor also in particularpartially on conventional materials for powder coating so as to providea coating material for NIP and/or that the processing of suchcompositions with a NIP method can be adapted so as to provide a curablecoating layer to a substrate.

However, only a certain window of adjustment of viscosity and reactivityof heat curable coating materials is suitable to provide high qualityprinting. Out of this window the quality could be bad because with toolow viscosity and/or too low reactivity the printed dots (sometimesreferred to as printed spots) would undergo too much viscous flow andintermix to each other and with too high reactivity the adhesion to thesubstrate and/or the surface quality (no smooth surface) could benegatively affected.

In this regard, it is noted that according to an embodiment both, theviscosity as well as the reactivity are considered to achieve thedesired results. For example, a lower viscosity may be acceptable (andmay provide sufficient resolution of the printing) if the reactivity issufficiently high such that on the timescale available for viscous flowthe amount of flow is small enough so as to not adversely affect thequality (and in particular the resolution) of the printing.

By taking the interplay between viscosity and reactivity into account,surprisingly characteristic properties of conventional powder coatingscan be achieved with coating layers generated by NIP, in someembodiments even if the layer thickness of the coating layer is smallerthan the corresponding thickness of the conventional powder coating.Hence, the efficiency of coating may be improved (i.e. less coatingmaterial is necessary for achieving the same properties) while on theother hand a high resolution print is possible.

According to an embodiment, a coating material for generating a coatinglayer by NIP is provided, wherein the coating material comprises acurable resin.

The interplay between viscosity and reactivity may be taken into accountby the different measures. For example, the coating material usuallyexhibits a minimum viscosity when being heated from room temperature upto a temperature where curing of the coating material occurs. This isdue to the fact that upon increasing the temperature the viscosity isusually reduced if no additional processes occur. On the other hand,when curing sets in the viscosity increases, leading to a (local)minimum in the viscosity at a certain temperature. Hence, in thispicture, for example a high reactivity of the coating material willshift the temperature at which the minimum viscosity occurs to a lowertemperature and hence the viscosity value at the minimum viscosity willbe higher (because the minimum is at lower temperature). Since theminimum viscosity also reflects the change of mechanical properties ofthe coating material with temperature as well as the curing dynamics,the minimum viscosity will usually depend on the heating rate.

The aforementioned concepts may be taken into account for defining ameasure which allows to determine whether or not a coating material issuitable for the desired NIP (digital printing) of a coating layergenerated from the coating material. According to an embodiment, acoating material is considered a suitable coating material if, with aheating rate of 5 Kelvin per minute (5 K/min), the minimum viscosity ofa suitable coating material is in a range between 3 Pascal seconds to10000 Pascal seconds. According to a further embodiment, with a heatingrate of 5 Kelvin per minute the minimum viscosity is in a range between50 Pascal seconds and 3000 Pascal seconds.

According to a further embodiment, a so-called a pill flow length testis used for determining as to whether a coating material is a suitablecoating material. According to an embodiment, a pill flow length of acoating material is determined according to embodiments of the hereindisclosed subject matter.

According to an embodiment, the pill flow length of the coating materialis below 350 mm at a potential curing temperature which may be used tocure the coating material.

Surprisingly, it was found that a coating material which exhibits theabove mentioned properties regarding minimum viscosity and/or pill flowlength can withstand the needed requirements for many industrialapplications and also the needs of high quality printing. According toan embodiment, the final curing of the coating layer may be performedthermally at the potential curing temperature (e.g. at 180°).

Coating materials according to the herein disclosed subject matter canbe built up by many different resin systems. The preferred systemcontains at least 30 w-%, preferably at least 50 w-% and most preferablyat least 75 w-% of an amorphous resin related to the overall amount ofresin. Surprisingly it was found that with such values high qualityprinting can be achieved. A higher content of crystalline resins lead toprintings which showed less resolution after heat curing. The used resinsystems can be different depending on the special needs of theindustrial applications. Potential resin systems (resin components) canbe polyester, epoxy, urethanes, acrylics, fluorocarbon resins orcombinations of two or more of these resin components. Some exemplaryembodiments are given in the following paragraphs. However, for a personskilled in the art it might be easy to find additional suitablecombinations based on the given principles.

The above mentioned resin systems can be modified by many differentoptions. For example additives like flow additives or leveling agentscan also influence the viscosity and a smooth surface. However,surprisingly it was found that the printing performance (in particularin respect to the printing quality) of the coating material was betterwhen a low concentration or even no flow additive or leveling agent wasadded. A concentration less than 1 w-% of leveling agent/flow additivewith regard to the entire coating material was used in some embodiments.According to another embodiment, less than 0.5 w-% and most preferablyless than 0.1 w-% of the leveling agent/flow additive with regard to theentire coating material was used in some embodiments. According to anembodiment, a cured coating layer (generated from a coating materialaccording to embodiments of the herein disclosed subject matter)comprises with respect to the entire amount of coating material of thecoating layer less than 1 w-%, in particular less than 0.5 w-%, furtherin particular less than 0.4 w-%, less than 0.3 w-% and preferably lessthan 0.1 w-% of flow additive.

The addition of fillers like CaCO3, talc, clay, mica, kaolin or bariumsulfate lead surprisingly to a loss of printing quality especially if,with regard to entire coating material, more than 1 w-%, or even morethan 5 w-% or even more than 10 w-% of inorganic filler material wasadded. However, in this regard, according to an embodiment titaniumoxide (titanium dioxide, TiO2) is not a filler but a pigment. In otherwords, fillers may be provided in an amount of less than 10 w-%, inparticular less than 5 w-%, further in particular less than 1 w-% basedon the overall amount of coating material, in accordance with anembodiment, despite the specified amount of filler, titanium oxide(titanium dioxide) may be included in a higher amount, e.g. according toembodiments disclosed herein. Further as mentioned herein, despite thespecified amount of filler silicon dioxide and/or titanium dioxide maybe used to improve the powder flow or charging properties of the coatingmaterial.

Surprisingly only a certain window of reactivity and viscosity, whichmay be determined according to embodiments of the herein disclosedsubject matter, led to high resolution printing performances in NIP(digital printing). With compositions out of this window during heatingup the likelihood of bad printing was very high. For example, bleedingeffects occurred in which single printing spots (e.g. of differentcolor) were mixing with each other during heating up, especially underindustrial conditions were the printed substrates are hold vertical in acuring furnace. Further, outside the specified window of reactivity andviscosity, which may be determined according to embodiments of theherein disclosed subject matter, a loss of contours of the printedcoating material layer appeared.

Usually for reactive high melting polyesters, esters of terephthalicacid (TPSA) are used, because they show a relatively narrow meltingregion due to their pronounced linearity (and therefore crystallinity),which furthermore correlates with the molecular weight. However, forcoating materials according to the herein disclosed subject matter, i.e.coating materials with thermosetting properties, surprisingly it turnedout that by turning away from the linear polyester and/or(semi)crystalline structure particular advantages in the processing canbe achieved: broader softening region, higher minimum viscosity,cross-linking to elastic cured coating layers/coatings which thoughcomply with the relevant tests for adhesion and resistance requirements(e.g. Erichsen test or methyl ethyl ketone test). This may in particularbe achieved by using different monomers, in particular aliphaticcomponents—if applicable also with sidechains, multi-functional monomers(for example trivalent organic carbon acids) or non-linear carbon acidsas for example isophthalic acid (IPSA). Already at least 5% of IPSAinstead of TPSA lead to a positive effect. Additionally, using IPSAleads to a higher weathering resistance of the cured coating layer.Polyester in which the TPSA has been replaced completely by IPSA showthe best weathering resistance among the polyesters. The amount of IPSAand/or TPSA may be determined during manufacturing of the resin and inparticular during polycondensation by using a mixture of both phthalicacids or by using a mixture of uniform polyesters in the desired ratio.

In particular for geometrically complex substrates according to anembodiment a coating is applied to a substrate by implementing thefollowing method:

-   -   1) Printing (e.g. by digital printing) a coating material        according to embodiments of the herein disclosed subject matter        on a transfer element (e.g. a transfer sheet)    -   2) Applying the printed transfer sheet to the substrate and        transfer the coating material (e.g. a coating layer formed        therefrom) to the substrate    -   3) Final curing of the print on the substrate

Between any two of the individual method steps 1, 2, and 3 a partialcuring (for example via radiation) can be implemented.

According to an embodiment, formulations of a coating material accordingto the herein disclosed subject matter includes at least 30 w-%, forexample at least 50 w-% and in particular at least 75 w-% of anamorphous resin with regard to the total amount of resin.

According to an embodiment, a coating material as described hereinshowed best printing performance when it was used as so called twocomponents (2K) system. A 2K system is commonly used inelectrophotographic printing. In a two components 2K—soft magnetic brushtechnology a soft carrier, in particular a ferrite core carrier, isused. Also other carriers known to persons skilled in the art areaccording to the invention. In particular the carrier surface can bebetween 500 and 1000 cm²/g and the average particle size of the carrierbetween 20 to 150 μm with coatings made of different resins likesilicone resin. Other embodiments work with a liquid carrier known inthe art. According to still other embodiments the coating material asdescribed herein is used as a monocomponent system (without carrier).

According to an embodiment, a printing unit according to the hereindisclosed subject matter is a 2K printing unit. In this case theprinting unit may include a carrier known in the art, e.g. a ferritecore carrier, e.g. in a developer of the (electrophotographic) printingunit.

According to a further embodiment, a coating material as describedherein comprises a charge control agent (CCA) in a concentration ofhigher than 0.1 w-%, for example higher than 1 w-% and in particularhigher than 2 w-% with regard to the overall coating material. It wasfound that such a concentration of a charge control agent may improvethe quality of the printing.

Surprisingly it was found that the color density was better with a CCAconcentration above 1 w-% with regard to the overall coating materialformulation. So therefor in particular this threshold was used for highquality printings independently of the charging effects. Even moresurprisingly it was found that not all CCA types lead to a coatingmaterial which fulfills the requirement of architectural applicationsconcerning UV/weather stability. Surprisingly CCAs comprising or basedon salicylic compounds showed high performance according to this aspect.Very good UV resistance was achieved when N-type (negative type)colorless CCAs, preferably zink salicylic comprising CCAs where used.

According to an embodiment the coating material has an absolute value ofchargeability of at least 5 μC/g, preferably of at least 10 μC/g andmost preferably of at least 20 μC/g and an activation time of 1 minuteto 15 minutes, for example 2 minutes to 10 minutes tested in a standard(e.g. soft blow) Epping q/m equipment.

Surprisingly it was found that the charging could also be influenced bythe addition of one or more of inorganic surface additives, preferablyinorganic oxides of silicon and/or titanium, for example with a d50particle size between 1 nanometer and 100 nanometer (e.g. d50=50nanometer), in particular with a particle size between 5 nanometer and70 nanometer. Further, it was surprisingly found that the addition of atleast two inorganic oxide components with different average particlediameter may improve the charging performance. In this regard, if thetwo inorganic oxide components with different average particle diameterare made of the same material, these two inorganic oxide components maybe considered equivalent to a single inorganic oxide component theparticle size distribution of which comprises two distinct maxima.According to an embodiment, the two inorganic oxide components are bothsilicon oxide powder but with different average particle diameter.According to an embodiment, the silicon oxide is silica. In particular,according to an embodiment, a ratio of the average particle diameter ofthe two inorganic oxide components (e.g. silica) is between 2 to 10, forexample between 5 to 7. According to a further embodiment, of the twoinorganic oxide components a first inorganic oxide component is siliconoxide with a particle distribution d50=50 nm and a second inorganicoxide component is silicon oxide with a particle distribution of d50=8nm.

According to a further embodiment, the coating material has an averageparticle diameter in a range between 1 μm and 25 μm, for example inbetween 5 μm and 20 μm with a particle size distribution of d10 in arange between 5 μm and 7 μm and/or of d50 in a range between 8 μm and 10μm and/or a d90 in a range between 12 μm and 14 μm. Herein and as isgenerally known, a specific value for dx (in the above examples x=10,50, 90) indicates that an amount x of the particles is smaller than thespecified size. For example, d10=5 μm specifies that 10% of theparticles are smaller or equal to 5 μm.

Preferably a sphericity of higher than 0.7, more preferably higher than0.9 is given. Interestingly it was found that in case of lowersphericity and/or bigger particle sizes of the coating material acertain haptic effect occurred in the final printing and/or final curedprinting layer which might be of an advantage for certain applications.

According to embodiments of the herein disclosed subject matter, acoating material may have a surprisingly high chemical resistancecompared to the state of the art. The chemical resistance can beinfluenced by many different aspects. Especially the type of resin (e.g.acrylic, polyester, etc.) and also the amount of functional groups haveshown to have a huge influence on the chemical stability. Principiallyit was found that the higher the crosslinking density of the curedsystem was the higher the chemical stability was given. Also it wasfound that acrylic and/or epoxy based coatings have given high chemicalstability. One embodiment is characterized by the fact that at least onetype of crosslinking agent is chosen in an amount suitable that thecoating material is able to reach a rating of at least 2-3 in theMethylethylketone-test after 10 s according to the DIN EN 12720. Forthis crosslinking material can be chosen fromepoxy/glycidyl-group-containing materials, including epoxy-resins,hydroxyalkylamide hardeners, isocyanate hardener and/or double bondcontaining compounds with a thermal radical initiator system. For thisthe curing agent is added in an amount between 0.3 to 1.7, preferably0.7 to 1.3 and most preferably 0.9 to 1.1 of the molar ratio sufficientto cure the at least one type of resin.

In another embodiment of the herein disclosed subject matter theresulting coating resists at least 50 IPA (Isopropyl alcohol) doublerubs and/or at least 5 acetone double rubs, in particular at least 10,in particular at least 20.

The low thickness of the coating layer which is sufficient to achieveresults comparable to conventional powder coatings is surprising inparticular because for powder coatings usually much higher thicknessesare necessary (e.g. GSB norm for architectural applications with aminimum thickness of 50 μm, EN 12206-1:2004 (D): a mean layer thicknessmust be at least 50 μm. No value below 40 μm is allowed, materials to becoded-coatings on aluminum and aluminum alloys for constructionalpurposes part one: coatings made of coating powders).

According to an embodiment, the coating is applied in more than onecoating layer and the coating material comprises a curable resin andwherein during each pass of the printing process the resin is at leastpartially subjected to viscous flow. This may improve the properties ofthe resulting coating. If during each pass of the printing process theapplied layer is subjected to partial curing, also cross-linking withthe previous layer may occur at this stage, i.e. before final curing ofthe coating (the layer package comprising at least two coating layers).

Also surprising was the fact that for the most industrial applicationscoatings with sufficient resolution can already be achieved with a ratioof the average particle diameter over the thickness of the coating layerof 1:2.

Further, it was found that the coating material with a suitable amountof curing agent and/or initiator for the cross-linking of the binder,can provide that the coating material according to ONORM EN 12720satisfied class IB after 10 seconds of acetone influence.

The coating material was found to be capable to be used as corrosionprotection, preferably if the thickness of the coating is at least 30μm, e.g. by two coating layers, in particular if the (two or more)coating layers are (at least partially) individually cured. If a firstcoating layer comprises a pinhole but is at least partially cured beforea second coating layer is applied on the first coating layer it isunlikely that the second coating layer comprises a pinhole at theexactly same location. Hence, the formation of pinholes in the finalcoating is avoided or at least reduced.

According to an embodiment, the coating material is configured for beingapplied with a thickness of at least 20 μm, in particular with athickness of at least 30 μm, further in particular with a thickness ofat least 40 μm.

According to a further embodiment, a ratio of the average particlediameter to a thickness of the coating layer is smaller than 1:2, inparticular smaller than 1:3, further in particular smaller than 1:4.

According to an embodiment, the coating material comprises a polyesterresin, and wherein the coating material is in particular bisphenol Afree and/or epoxy free or at least BPA was not intentionally added asraw material.

According to a further embodiment, the polyester resin comprises an(incorporated) acid monomer and wherein at least 25 w-% of the acidmonomer is isophthalic acid, in particular at least 50 w-% of the acidmonomer is isophthalic acid; and further in particular at least 85 w-%of the acid monomer is isophthalic acid.

According to an embodiment, a minimum glass transition temperature ofthe coating material (e.g. a glass transition temperature of the uncuredcoating material) is below 80° C., in particular below 60° C.

According to an embodiment, the remaining gloss after 300 hours of UVexposure, determined according to ISO 2813, is at least 50% for thecured coating. A remaining gloss after 600 hours of UV exposureaccording to the test procedure of GSB internationalAL631-PartVII-segment 20.1 Kurzbewitterung UV-B (313) is at least 50%,in particular at least 85%; a remaining gloss after 1000 hours of Xenonexposure according to EN ISO 16474-2 determined according to ISO 2813,is at least 50%, in particular at least 85%.

According to an embodiment, the coating material is configured to,besides forming a part of a coating layer representing an imagecomprising one or more different colors, in particular at least twodifferent colors, serve in addition at least one of the followingfunctions: ceiling, high-temperature resistance, weathering resistance,long-term ultraviolet stability, wearing coat, being free from pinholes,wear based bleaching protection, outdoor capability, scratch resistance,resistance to solvents, diffusion reduction function. It is noted thataccording to an embodiment any optically distinguishable contrast isconsidered as being formed from two different colors (e.g. even parts ofa coating layer formed from a coating material of a same color but wherethe parts comprise a different surface structure).

According to a further embodiment, the coating material comprises anamount of 0.1 w-% to 10 w-% of a charge control agent, wherein thecharge control agent in particular comprises or consists of one or moresalicylic acid zinc compounds (zinc salicylic compounds). According to afurther embodiment, the coating material comprises an amount of 0.2 w-%to 5 w-% of a charge control agent or, in another embodiment, an amountof 0.5 w-% to 3 w-%.

According to an embodiment, the coating layer is applied to a targetsurface. Herein, a target surface is a desired surface on to which thecoating layer is to be applied. The target surface may be formed e.g. bya transfer element if the printing method uses a transfer element.According to another embodiment, the target surface may be formed by thesubstrate, in case of a direct printing method.

According to a further embodiment, the coating material is a powderycoating material. Further, while some embodiments of the hereindisclosed subject matter refer to a powdery coating material, it shouldbe understood that the use of a liquid (e.g. as a transfer medium inwhich the powdery coating material is dispersed, or as a solvent inwhich the coating material is dissolved) is also contemplated. However,since after evaporation of the liquid the coating material remains asthe coating layer on the desired surface, using a liquid in combinationwith a coating material according to embodiments of the herein disclosedsubject matter is easily applied and taken into account by a skilledperson.

According to a further embodiment, the coating material is thermallycurable, in particular at least partially thermally curable. Thermallycuring provides an efficient method, in particular for curing a largenumber of substrates having the coating layer thereon. Furthermorethermally curing offers a wide range of powder coating chemistry whichis known to fulfill industrial needs which current toner technologiescannot provide. According to an embodiment, when applied to thesubstrate the coating layer according to embodiments of the hereindisclosed subject matter is finally cured. It should be understood thatfinally curing does not mean that there is not any residual uncuredmaterial in the finally cured coating layer. Rather, final curingrelates to curing to a degree that is necessary to achieve the desiredproperties of the thus cured coating layer.

According to an embodiment, a coating layer application devicecomprises: a transfer element support for supporting a transfer elementaccording to the fourth aspect; a substrate support for receiving asubstrate onto which the coating layer shall be applied, wherein thetransfer element support and that the substrate support are operable tobring the coating layer on the transfer element in contact with thesubstrate in order to apply the coating layer to the substrate; aheating device being configured for heating the coating layer on thetransfer element; and a control device configured for controlling theheating device so as to (i) maintain the temperature of the coatinglayer below a first temperature before removal of the transfer elementfrom the coating layer, wherein at the first temperature the uncuredcoating material is in its supercooled liquid state or in its glassystate; and/or (ii) partially cure the coating layer during the contactof the coating layer and the substrate and before removal of thetransfer element from the coating layer, in particular by increasing thetemperature of the coating layer to a temperature at or above a curingtemperature of the coating layer.

According to an embodiment, the curing temperature is equal or higherthan the start temperature of the curing reaction determined accordingto ISO 12013-1:2012 Paints and varnishes—Determination of curingcharacteristics using a free damped oscillation method—Part 1: Starttemperature of the curing reaction. According to a further embodiment,the curing temperature of the coating material is higher or equal to atemperature at which after maximal 60 minutes no more heat is generatedand/or consumed by the coating material and/or the Tg of the curedcoating after maximal 60 min at a certain temperature is changing notmore than 5° C., in particular not more than 3° C. in a DSC measurementwhen measured first time during the first heating up and measured asecond time during a second heating up with 20 K/min and between thefirst and second heating up the coating was hold for 15 min at atemperature well above—at least 10° C. above—the curing temperature.According to a further embodiment, the curing temperature of the coatingmaterial is equal or higher than a temperature at which after 60 minutesno more heat is generated and/or consumed by the coating material.

The lowest temperature among the curing temperatures determined by themethods disclosed herein may be considered as a lowest possible curingtemperature. In order to achieve time-efficient coating processes, anactually chosen curing temperature may be higher than the lowestpossible curing temperature or higher than a curing temperaturedetermined by the methods disclosed herein.

According to an embodiment, the method further comprises: providing atransfer element according to one or more embodiments thereof; bringinginto contact the coating layer on the transfer element and the substratein order to apply the coating layer to the substrate; controlling atemperature of the coating layer on the transfer element so as to (i)maintain the temperature of the coating layer below a first temperaturebefore removal of the transfer element from the coating layer, whereinat the first temperature the uncured coating material is in itssupercooled liquid state or in its glassy state; and/or (ii) partiallycure the coating layer during the contact of the coating layer and thesubstrate and before removal of the transfer element, in particular byincreasing the temperature of the coating layer to a temperature at orabove a curing temperature of the coating layer.

According to an embodiment, the coating layer is transferable to asubstrate and comprises a polyester resin, wherein the polyester resinis in particular bisphenol-A free and/or epoxy free (or the respectiveamount is at least below 1 w-%, in particular below 0.1 w-%) and/or athermosetting resin.

According to an embodiment, the coating layer (in particular the curedcoating layer) comprises a charge control agent.

According to an embodiment, the printing device comprises: a printingunit being configured for applying the coating material to a transferelement; and an energy transfer device being configured for transferringenergy to the coating material on the transfer element; wherein inparticular the energy transfer device is configured for transferring theenergy to the coating layer so as to partially cure the coating layer onthe transfer element and/or to induce viscous flow in the coating layeron the transfer element.

According to a further embodiment, instead of printing on a transferelement, the printing device is configured for printing directly on asubstrate to be coated.

Regarding processing of the coating layer, it was found that it isadvantageous to avoid for the coating layer as far as possible atemperature range between a melt temperature and a curing temperature ofthe coating layer before removal of the transfer element from thecoating layer, if such a melt temperature exists (i.e. if the coatinglayer contains a material portion which exhibits a melt temperature). Inother words, embodiments of the herein disclosed subject matter arebased on the idea that it is advantageous to (i) maintain thetemperature of the coating layer below a first temperature beforeremoval of the transfer element from the coating layer, wherein at thefirst temperature the uncured coating material is in its supercooledliquid state or in its glassy state, and/or (ii) partially cure thecoating layer during the contact of the coating layer and the substrateand before removal of the transfer element from the coating layer, inparticular by increasing the temperature of the coating layer to atemperature at or above a curing temperature of the coating layer. Asdescribed in more detail below, the supercooled liquid state is abovethe glass transition temperature Tg and below the melt temperature Tm,if such a melting temperature is existing.

In curable polymers, usually the glass transition temperature raiseswith time and curing degree. Therefore, if at the first temperature theuncured coating material is in its supercooled liquid state or in itsglassy state, this implies that at the first temperature also thecoating layer as received with the transfer element in the transferelement support is in its supercooled liquid state or in its glassystate.

According to an embodiment, the coating layer comprises a crystallinephase or can be at least partially brought into the crystalline phase,wherein the crystalline phase defines a melt temperature and the firsttemperature is below the melt temperature.

According to a further embodiment, the coating layer application devicefurther comprises a printing device being configured for applying thecoating material to the transfer element by printing to thereby form thecoating layer. According to an embodiment, the printing device is a NIPdevice or a digital print device. NIP or digital printing may use one ormore of electric fields (e.g. electrographic methods), magnetic fields(e.g. magnetic graphic methods), ions (e.g. ionographic methods),inkjets (inkjet methods), thermographic methods and photographic methodsfor generating an image made from coating material on a transferelement.

According to an embodiment, the printing device for generating thecoating layer on the transfer element is a separate device and may begeographically separated from the coating layer application device whichapplies the coating layer to the substrate. Accordingly, the transferelement with the coating layer thereon may be removable from theprinting device, e.g. for shipment, storage, etc. According to anembodiment, one or more transfer elements are being provided. Further,it is noted that two or more transfer elements may be provided, e.g. twotransfer elements wherein the printing device is configured for printingon a first transfer element and wherein the printing device isconfigured for transferring the coating layer from the first transferelement (e.g. an intermediate transfer element) to the second transferelement. In such a case, it is the second transfer element (or generallythe last transfer element) with the coating layer thereon that istransferred to the coating layer application device (which may be astandalone coating layer application device, e.g. a coating layerapplication device which is configured for solely applying the coatinglayer to the substrate).

According to a further embodiment, the printing unit (or printingdevice) comprises a single, removable transfer element. Further it isnoted that the removable transfer element may also be referred to (andis herein also referred to) as a standalone transfer element, and viceversa.

Accordingly, in an embodiment the transfer element having the coatinglayer thereon (e.g. the single transfer element or the second transferelement) is a separate part and the transfer element support isconfigured for receiving the transfer element having the coating layerthereon as a separate part.

According to an embodiment, the coating material is a powdery coatingmaterial. This may provide the advantage that experience andunderstanding of properties of conventional powder coatings may be usedfor and/or transferred to a coating material according to embodiments ofthe herein disclosed subject matter.

According to an embodiment, the printing device is configured forapplying the coating material to the transfer element with a thicknessof (i.e. the coating layer has a thickness of) at least 10 μm, inparticular with a thickness of at least 20 μm, for example with athickness of at least 40 μm. While in many known applications for tonera smallest as possible thickness is desirable to safe material costs asthere is no technical need for higher coating thicknesses, embodimentsof the herein disclosed subject matter may provide for even thickercoating layers.

According to an embodiment, the printing device is configured forapplying the coating material as an image comprising one or moredifferent colors, in particular at least two different colors, to thetransfer element. According to an embodiment, the coating layer maycomprise a single color or two or more different colors (coatingmaterials).

According to an embodiment, the image extends entirely through thecoating layer in a direction perpendicular the coating layer. In thisregard it is noted that if the coating on the transfer element includestwo or more layers, the image does not necessarily extend also throughthe other layers, although this is the case in an embodiment.

According to a further embodiment, the printing device is configured forapplying the image of the coating material to the transfer element witha resolution of more than 2 l/mm, in particular with a resolution ofmore than 5 l/mm, e.g. with a resolution of more than 10 l/mm. Generallyherein, the term “resolution” refers to a lateral resolution in theplane of the coating layer unless indicated otherwise. Numerousembodiments of the herein disclosed subject matter may assist inachieving the desired resolution, as is described in detail below.

According to an embodiment, the coating layer application device (or theprinting device) further comprises an energy transfer device beingconfigured for transferring energy, in particular heat, into the coatingmaterial on the transfer element before the contact of the coating layerand the substrate. According to a further embodiment, the energytransfer device is configured for transferring the energy to the coatinglayer so as to partially cure the coating layer on the transfer element.According to another embodiment, the energy transfer device isconfigured for transferring energy to the coating layer so as toinitiate viscous flow in the coating layer.

According to an embodiment, the coating layer is compacted by acompaction device configured for compacting the coating layer on thetransfer element (e.g. the standalone transfer element) before thecontact of the coating layer and the substrate. According to anembodiment, the compaction device is configured (e.g. located) so as tocompact the coating layer before, during or after the energy transfer bythe energy transfer device. According to an embodiment, the coatinglayer application device is configured for applying to the coating layera pressure, in particular a pressure of more than 0.1 bar, in particularmore than 1 bar, in particular more than 3 bar, in particular more than5 bar and further in particular more than 10 bar.

According to a further embodiment, the coating layer application device(or the printing device) further comprises a compaction deviceconfigured for compacting the coating layer on the transfer elementbefore the contact of the coating layer and the substrate, e.g. acompaction device configured as described herein.

According to an embodiment, the printing device comprises one or moreprinting units, e.g. a single printing unit. According to an embodiment,the printing device comprises two or more printing units. According to afurther embodiment, the two or more printing units are configured forapplying two or more different coating materials (e.g. coating materialsof different color) to the transfer element to thereby form the coatinglayer (e.g. a two or more color coating layer, in particular a coatinglayer representing an image) on the transfer element. According to afurther embodiment, the two or more printing units are configured forapplying the same coating material to the transfer element to therebyform the coating layer on the transfer element (with a largerthickness).

According to an embodiment, the printing device provides a transferelement, in particular a standalone transfer element, comprising acoating layer, the coating layer being formed from a coating material,the coating layer being curable and comprising an amorphous material,wherein the coating layer is transferable to a substrate and comprises apolyester resin, wherein the polyester resin is in particularbisphenol-A free and/or epoxy free and/or is a thermosetting resin.According to a further embodiment, the coating material and hence thecured coating layer comprises a charge control agent.

According to a further embodiment, there is provided a method ofoperating a coating layer application device comprising a transferelement support, a substrate support, and a heating device, the methodcomprising: receiving by the transfer element support a transfer elementcomprising a coating layer, the coating layer being formed from acoating material, the coating layer being curable and comprising anamorphous material; receiving by the substrate support a substrate ontowhich the coating layer shall be transferred, wherein the transferelement support and the substrate support are operable to bring thecoating layer on the transfer element in contact with the substrate inorder to apply the coating layer to the substrate; operating the heatingdevice so as to (i) maintain the temperature of the coating layer belowa first temperature before removal of the transfer element from thecoating layer, wherein at the first temperature the uncured coatingmaterial is in its supercooled liquid state or in its glassy state;and/or (ii) to partially cure the coating layer during the contact ofthe coating layer and the substrate before removal of the transferelement from the coating layer, in particular by increasing thetemperature of the coating layer to a temperature above the curingtemperature. It is noted that by increasing the temperature of thecoating layer to a temperature above the curing temperature usuallyleaves the temperature range in which the uncured coating material is inits supercooled liquid state or in its glassy state. Hence, in this casethe “or” of the “and/or” combination of features (i) and (ii) applies.

According to an embodiment, the transfer element support and thesubstrate support are operable to bring the coating layer on thetransfer element in contact with the substrate and apply the coatinglayer to the substrate with a pressure, in particular a pressure of morethan 0.1 bar, in particular more than 1 bar, in particular more than 3bar, in particular more than 5 bar and further in particular more than10 bar, e.g. with a pressure in a range between 3 bar and 10 bar, e.g.between 5 bar and 8 bar.

It is further noted that according to an embodiment of one of theaspects mentioned herein, the respective entity (device, method, etc.)is adapted for providing the functionality or features of one or more ofthe herein disclosed embodiments and/or for providing the functionalityor features as required by one or more of the herein disclosedembodiments, in particular of the embodiments of the other aspectsdisclosed herein.

The control device may be implemented by at least one of mechanics,hardware and software. For example, the control device may comprise theprocessor device and the computer program product according toembodiments of the herein disclosed subject matter, e.g. a memory forstoring the program element.

As used herein, reference to a computer program product is intended tobe equivalent to a reference to a computer program and/or a computerreadable medium containing a program element as described herein, inparticular for controlling a processor device to effect and/orcoordinate the performance of a method as described herein. According toan embodiment, the processor device is a network node and/or a computercomprising a memory and at least one processor for carrying outinstructions defined by the program element.

The computer program may be implemented as computer readable instructioncode by use of any suitable programming language, such as, for example,JAVA, C++, C #, etc., and may be stored on a computer-readable medium(removable disk, volatile or non-volatile memory, embeddedmemory/processor, etc.). The instruction code is operable to program acomputer or any other programmable device to carry out the intendedfunctions. The computer program (as well as any data) may be availablefrom a network, such as the World Wide Web, from which it may bedownloaded. Any suitable aspect or embodiment of the herein disclosedsubject matter may be realized by means of a computer programrespectively software. However, the herein disclosed subject matter mayalso be realized by means of one or more specific electronic circuitsrespectively hardware. Furthermore, the herein disclosed subject mattermay also be realized in a hybrid form, i.e. in a combination of softwaremodules and hardware modules.

In the above there have been described and in the following there willbe described exemplary embodiments of the subject matter disclosedherein with reference to a coating layer application device, a method, acomputer program product, a printing device, a transfer element and asubstrate. It has to be pointed out that of course any combination offeatures relating to different aspects of the herein disclosed subjectmatter is also possible. In particular, some features have been or willbe described with reference to device type embodiments (e.g. relating toa coating layer application device, a printing device, or a controldevice thereof) whereas other features have been or will be describedwith reference to method type embodiments (e.g. relating to a method ora computer program product). However, a person skilled in the art willgather from the above and the following description that, unlessotherwise notified, in addition to any combination of features belongingto one aspect also any combination of features relating to differentaspects or embodiments, for example even combinations of features ofdevice type embodiments and features of the method type embodiments areconsidered to be disclosed with this application. In this regard, itshould be understood that any method feature derivable from acorresponding explicitly disclosed device feature should be based on therespective function of the device feature and should not be consideredas being limited to device specific elements disclosed in conjunctionwith the device feature. Further, it should be understood that anydevice feature derivable from a corresponding explicitly disclosedmethod feature can be realized based on the respective functiondescribed in the method with any suitable device disclosed herein orknown in the art.

Embodiments of the herein disclosed subject matter are based on the ideathat with suitable adaptions printing principles known from NIP, such asimage print, laser print, etc. can be used to apply a coating materialwhich has properties of typical powder coating materials to a substrate.To this end, it may be necessary to form a coating layer of the coatingmaterial with a suitable thickness which is usually higher thanconventional toner thicknesses used in laser printing (e.g. 5 μm to 10μm). Even more, while in a conventional digital printing technologieshigh efforts are made to reduce the toner thickness in order to reducecosts, for the intended applications of the herein disclosed subjectmatter it is advantageous to have higher thicknesses, for example above10 μm.

According to an embodiment, the coating material comprises an amorphousmaterial the properties of which are used to achieve the desired coatinglayer.

In one example, NIP based transfer systems are used to realize aspectsand embodiments of the herein disclosed subject matter. According to afurther example, a NIP based transfer method is used to provide thecoating layer entirely colored throughout its layer thickness. Accordingto a further example, a NIP based transfer method is used to provide thecoating layer with a high resolution throughout its layer thickness.

Known NIP systems are often large or located in a central infrastructureto provide a direct print onto a desired material. Further, thegeometries for direct print are limited regarding printing width,unevenness of the desired material, or capability of printing on 3Dparts. Conventional powder coating systems, which usually operate withspray guns from which the powder is provided by means of pressurizedgas. After application of the powder on the desired material (alsoreferred to as substrate) the powder is heated so as to transform into acontinuous layer. Coating materials of conventional powder coatingtechnologies are not suitable for (direct or indirect) NIP, inparticular NIP based transfer systems because the size of the powderparticles is too big for NIP based methods, especially when highresolution printing is desired.

However, surprisingly chemically curable coating materials with aparticle size distribution (PSD) that is suitable for a NIP system (e.g.mean size of approximately 9 μm and a spread of a Gaussian distributionof particle sizes of 5 μm to 16 μm) are suitable for providing thickcoating layers via a NIP method. According to other embodiments, themean size of the particle size distribution of the curable coatingmaterial is in a range between 5 μm and 15 μm. The PSD according toembodiments of the herein disclosed subject matter facilitates anapplication of a thinner coating layer (e.g. with a thickness in a rangebetween 15 μm and 50 μm (compared to conventional powder coatings havinga typical thickness between 30 μm to 200 μm) which may still have thesame chemical and physical properties as conventional powder coatings.Without being bound to theory, the reason is thought to be theuniformity of the powder particles, the small particle size distributionwhen compared to conventional powder coatings and the lack of fillersand additives. In this regard, it is again noted that a thickness in arange between 15 μm and 50 μm is exceptionally thick compared toconventional toners of conventional NIP systems (which are applied in athickness of typicality 2 μm to 10 μm).

For coatings generally the following principles apply: the thinner thecoating the better are its mechanical properties, the thicker thecoating the better are the chemical properties, the aberration behaviorand the ultraviolet (UV) stability. Further, scratch force exerted witha pointed object has to be the higher, the thicker the coating layer isin order to penetrate the coating entirely down to the substrate. Hence,scratch resistance is improved by thicker coatings.

Transfer systems may have the problem of the insufficient adherence ofthe coating material on the substrate or too high adherence of thecoating material on transfer elements (resulting in difficulties in theremoval of the coating material from transfer element). A crystallinematerial usually has a small transition region between solid and liquidstate. This may result in a small thermal process window for goodadherence of the coating layer on the substrate and the removal of thetransfer element without adversely affecting the coating layer.

The lateral resolution achieved in the application of the coatingmaterial is often an essential quality feature of the transfer processin which the coating material is transferred by the transfer elementfrom a printing device to the substrate. Hence, a high amount ofcrystalline material may reduce the achievable resolution due to thesmall transition region between solid and liquid state.

For a coating layer which is an image comprising at least one or moredifferent colors, in particular more than two different colors, it isadvantageous to have the coating layer entirely colored throughout itslayer thickness, in particular regarding ablation and/or bleaching ofcoating material due to environmental impact (e.g. wind, sand, rain,solar radiation). In this regard, it is also advantageous to have asimilar resolution of the image throughout the layer thickness of thecoating layer.

Further, it is advantageous to prevent cracks or openings in in thecoating layer on the substrate (e.g. allgae may grow in cracks in anoutdoor application, in particular visible in transparent protectioncoating layers). Especially this is very critical when the coatingadditionally fulfills corrosion protection aspects which can be achievedby curable, especially heat curable coatings which comprise at least acurable resin together with at least one curing agent, according to theinvention.

Further, in many applications a glossy surface is desirable. Accordingto an embodiment, the coating material is configured for providing aglossy surface.

In an embodiment also very low gloss levels below 35, in particularbelow 30, in particular below 20 and even in particular below 10measured at a specular angle of 60 degrees according to ISO 2813 can bereached. One solution for this is the use of at least two differentresin systems in a coating material which provides different viscositiesand/or different reactivities during curing, in particular by differentamount of functional groups in the resins.

The above mentioned advantages may be supported or achieved by providingthe coating layer with a suitable thickness, e.g. with a thickness of atleast 5 μm, at least 10 μm, at least 20 μm, at least 30 μm or at least40 μm.

By the use of coating material according to embodiments of the hereindisclosed subject matter various advantages may be achieved inparticular by suitable processing of the coating material as describedherein. For example, according to an embodiment the coating materialcomprises a resin and the resin comprises an amorphous resin componentin an essential amount, for example in an amount of at least 35% atleast 50%, at least 60%, at least 70% or at least 80%. The percentagesin this case are referring to the amount of amorphous resins in theoverall resin composition of the coating material independently of theother ingredients. Purely amorphous resin is also possible.

In achieving various advantages mentioned herein, the temperature spreadof the flow properties of the amorphous material in the coating materialis helpful and may be advantageously combined with suitable processwindows as disclosed herein. In this regard, relevant process parametersmay be absolute temperature, temperature change cycles, the product oftemperature and exposure in time, temperature change rate, pressure,force impact (e.g. mechanical and/or magnetic forces), radiation (e.g.ultraviolet radiation), surface adherence control (mechanical design,contact angle, contact angle depending on temperature), etc.

Using a coating material which comprises an amorphous material andavoiding as far as possible a temperature window between a melttemperature of the coating material (if such a melt temperature occursunder the process conditions) and the curing temperature is advantageousin achieving or supporting the above mentioned advantages, in particularwith the higher amounts of crystalline resins, in particular above 10w-%. In particular, by avoiding this temperature window a high lateralresolution can be achieved. Further, running of different dyes into eachother may be avoided. Further, a high edge steepness can be achievedwhich provides for no or minimal change of an image of the coating layerupon abrasion of the coating layer.

As is commonly known and generally herein, the supercooled liquid rangeis considered as a temperature range between the glass transitiontemperature and the equilibrium melting/crystallization temperature.However, compared to crystallization in simple, small molecules, polymercrystallization occurs even further away from the thermodynamicequilibrium. However, the crystalline state is not always reachable,depending on the material (e.g. the chain structure of a polymer). Belowthe equilibrium melting temperature, the Gibbs free energy of theisotropic liquid is always higher than that of the crystalline solid.Therefore the supercooled liquid is, by definition, thermodynamicallymetastable. (Stephen Z. D. Cheng, “phase transitions in polymers, therole of metastable states”, Elsvier, 2008, page 78, 1.1). The timescaleon which crystallization occurs is known to depend on a number offactors which are not discussed here.

FIG. 1 shows schematically the behavior of a glass-forming material inparticular regarding an extensive property such as volume or freeenthalpy (see for example: S. R. Elliot, “Physics of amorphousmaterials”, Longman Scientific & Technical, 2nd edition, 1990).Exemplarily, in FIG. 1 the volume V of the material is plotted over thetemperature T.

Starting at a temperature above the melt temperature Tm, in the liquidphase and cooling down, the volume changes according to its coefficientof thermal expansion of a liquid state 120. At the melt temperature Tmin thermodynamic equilibrium the material crystallizes forming acrystalline state 122. If crystallization does not occur, the materialis supercooled into a supercooled liquid state 124. The transition fromthe liquid state 120 into the supercooled liquid state 124 is smooth andno phase transition (or sharp change in volume) occurs at the meltingtemperature Tm. For example, the coefficient of thermal expansion (theslope of the curve shown in FIG. 1) in the liquid state 120 and thesupercooled liquid state 124 is similar. Upon further cooling, at atemperature, which is referred to as the glass transition temperatureTg, the coefficient of thermal expansion changes to a value which iscomparable to the thermal expansion of the crystalline state 122. Hence,although below the glass transition temperature Tg the material stillexhibits an amorphous (disordered) structure its properties are similarto a solid. Usually the state 126 below the glass transition temperatureis referred to as glassy state (or vitreous state). It should beunderstood that FIG. 1 and the above explanation is provided fordescribing some principle aspects of amorphous materials while in somematerials, in particular in curable resins one or more of the abovementioned states, in particular the liquid state 120, may not bereachable because curing may set in at lower temperatures.

Generally herein, unless stated otherwise, a melting temperature orcrystallization temperature refers to the equilibriummelting/crystallization temperature. While this temperature may bedifficult to measure directly, the equilibrium melting/crystallizationtemperature may also be determined by extrapolation, as is known in theart.

Further, it is well known that a glass transition temperature of anamorphous material and in particular of an amorphous thermosettingpolymer depends on the degree of cure (often denoted as “alpha”, α), andon the method used for the measurement of the glass transitiontemperature. According to an embodiment, the glass transitiontemperature referred to in this document is the onset point of the glasstransition measured with a heating rate of 20 K per minutes in a DSCexperiment. In another embodiment, the glass transition temperaturereferred to in this document is the inflection point of the glasstransition measured with a heating rate of 20 K per minutes in a DSCexperiment. Generally herein, a material is considered an amorphousmaterial if the material is amorphous in the coating material, i.e. inthe powder before it is applied on the transfer element.

In order to facilitate understanding of the behavior of amorphousmaterial and in particular of an amorphous thermosetting polymer, timetemperature transformation diagrams (TTT diagrams) have been introduced(see e.g. John K Gillham, Polymer Engineering and Science, 1986, volume26, number 20, pages 1429 to 1433, in particular page 1430).

FIG. 2 schematically shows a simplified TTT diagram 100 indicating thetransformation of a thermosetting polymeric material with respect totemperature T and the logarithm of time t. In the TTT diagram 100 afirst line 102 indicates the transformation from a vitreous or a glassystate 104 (hatched area) to a supercooled liquid state 106 (unhatchedarea) or vice versa. Accordingly, the first line 102 indicates the glasstransition. Further indicated in the TTT diagram 100 is a gelation line108 which indicates the transformation from the supercooled liquid state106 into a gelled state above the gelation line 108. As is known, theability of a polymer to flow essentially stops at the gelation line 108.

At the time t=0 the first line 102 indicates the glass transitiontemperature for the uncured polymer which is often referred to as Tg0.As can be seen from the TTT diagram 100, maintaining the polymer at atemperature T1 (this would correspond to a horizontal line in thediagram 100, not shown) does not result in a transformation. Maintainingthe system at a higher temperature T2 would result in gelation of thepolymer at a time t1 and would result in vitrification of the polymer(i.e. transition into the glassy state, in particular into a gelledglass) at a time t2.

As can be taken from the TTT diagram 100, after maintaining thetemperature below Tg0 for a processing time tx>t3, the formation of thesupercooled liquid is avoided but an increase of the temperature (evenup to the curing temperature, not shown in FIG. 2) does not result in atransition into the supercooled liquid state but rather in gelation ofthe polymer at a temperature Tx. In other words, by suitable processingof the thermosetting polymer gelation (and hence curing) can be achievedeven by avoiding the supercooled liquid state. However, in order toincrease the speed of the process, usually a temperature in thesupercooled liquid state would be preferred.

Operation in the supercooled liquid or in the glassy state (i.e.avoiding of the liquid state above the melt temperature) can effectivelyprevent the lateral flow of the material of the coating layer in theplane of the coating layer (such flow can give rise to blurringlaterally defined edges (e.g. if the coating layer includes charactersor other fine structures) or in merging of different adjacent colors(running of different colors into each other) in the coating layer. Thisundesired flow of the material of the coating layer may be less of aproblem for horizontally oriented substrates but may be more pronouncedfor vertically oriented substrates since in this case gravity is actingon the material in the plane of the coating layer.

If the liquid state above the melt temperature is not avoided, this mayresult in the formation of undesired drops in the coating layer, inparticular if the curing temperature is not reached fast enough, whichagain rises the viscosity.

Since the coating layer on the transfer element usually cannot behardened so as to be dimensionally stable during the transfer, it isadvantageous if the transfer element has a high lateral stability (i.e.if it does not undergo plastic deformation and has a relatively highelastic modulus in the lateral direction (i.e. in the plane parallel tothe coating layer). Further, it is helpful if the transfer element ispeelable from the coating layer after the coating layer has beenattached to the substrate. For example, according to an embodiment thetransfer element is flexible perpendicular to its main surface on whichthe coating layer is deposited. For example, this may be achieved bycross laminated foils which are longitudinally stable in one directionsuch that by cross lamination (lamination of individual foils onto eachother wherein the foils are oriented transverse (e.g. perpendicular) toeach other) a high stretch resistance in both coordinate directions isachieved. In this regard, a sufficient lateral stability may be achievedwith a rather thin foil. A thin foil on the other hand provides for goodflexibility which facilitates the peel off of the thin foil (transferelement). However, according to other embodiments any suitable transferelement may be used, such as a transfer foil, a transfer belt, atransfer plate, etc.

According to an embodiment, the transfer element is transported by atransport device which may include a transfer belt carrying the transferelement. In direct printing embodiments, the transfer element isreplaced by the substrate to be coated.

Using a transfer element may be advantageous compared to direct printingbecause it allows a partial curing of the coating material on thetransfer element. The partial curing of the coating material on thetransfer element (before it is brought in contact with the substrate) isalso referred to as pre-curing herein. The pre-curing may provide easieraccessible processing windows and may increase the quality of the fullycured coating layer. Also regarding the pre-curing amorphous materialshave advantages compared to crystalline materials since crystallinematerials may have smaller processing windows. By using a coatingmaterial which is a combination of crystalline material and amorphousmaterial (e.g. a crystalline resin and an amorphous resin) or by using acoating material the resin of which is purely amorphous it is possibleto configure the coating material in various ways by one or more of theparameters time, pressure and heat. It is noted that according to anembodiment also a coating layer on a substrate (e.g. applied by directprinting onto the substrate) may be subjected to partial curing asdescribed herein, in particular by UV curing.

In particular, the amorphous material allows a flexible transfer of thecoating layer on the transfer element (e.g. it allows tailoring theproperties of the coating layer to the particularities of the transfer,e.g. by keeping the coating layer mechanically flexible) while on theother hand providing sufficiently high viscosity that during thetimescale of the transfer the material of the coating layer does notundergo the detrimental flow. Further, the viscosity of the amorphousmaterial can be adjusted (e.g. by the temperature) such that the coatinglayer thus sufficiently adheres onto the substrate without reducing alateral resolution in the plane of the coating layer.

According to an embodiment, the pre-curing is performed at temperaturesoutside the temperature window which extends between the melttemperature and the curing temperature. In other words, the pre-curingis performed either in the supercooled liquid state or above the curingtemperature. In this regard, it should be understood that the timeneeded to reach a certain partial curing state strongly depends on thetemperature and is generally higher for lower temperatures.

Besides the advantages regarding pre-curing, transfer systems (i.e. theuse of a transfer element) may be accompanied by problems of thedetachment of the transfer element from the coating layer afterattachment of the coating layer to the substrate. The inventive solutionallows a preconditioning of the coating layer in a way that theadherence between powder particles or a film formation is alreadyadvanced such that the adherence between the coating layer and thetransfer element is minimized after applying the coating layer to thesubstrate. In this way, a detachment of the transfer element from thecoating layer is achieved without difficulty after the coating layer hasbeen applied to the substrate. This may be further supported byproviding the transfer element with a material that reduces theadherence (e.g. by providing the transfer element with Teflon) or byprinting different layers and including in the coating layer near to thetransfer element (e.g. a transfer foil) a substance reducing theadherence to the transfer element. Another option could be to make apre-curing for the coating layer near to the transfer element—inparticular with UV—before applying the coating layer to the transferelement and therefore reduce the adherence of the coating layer to thetransfer element depending on the curing degree. Another possibility ofsupporting the detachment of the transfer element from the coating layeris to use a structured transfer element, e.g. by using a perforatedfoil, a foil with lotus effect, etc. Another possibility of supportingthe detachment of the transfer element from the coating layer is toprovide a transfer element with a structured surface (e.g. with asurface structure similar to a tissue or with a certain surfaceroughness). Another possibility of supporting the detachment of thetransfer element from the coating layer is to provide a suitabledetachment facilitating material between the transfer element and thecoating layer. A detachment facilitating material may be for example afluidic intermediate layer or a release powder.

Embodiments of the herein disclosed subject matter combine materialsconventionally used for powder coating with materials which areconventionally used for the manufacture of toners. According to anembodiment, by additional means (e.g. optimized charge control agents,CCAs in small amounts) a larger thickness of the coating layer isachieved.

According to an embodiment, a larger thickness may also be supported bya thicker coating of the transfer element (e.g. a thicker coating of atransfer drum by a developer unit) or by intermediate mechanicalcompaction. Due to the use of amorphous materials an additional rapidadherence of the coating material particles among each other is achievedduring the transport phase between latent image generation and theoptional pre-curing: by a pressure based compaction of the coating layerat the temperature close to the glass transition temperature Tg anamorphous component of the coating material a high inter-particleadherence is achieved. The inter-particle adherence allows an embeddingof further amorphous components of the coating material which are belowglass transition temperature thereof and/or an embedding of crystallinecomponents of the coating material which are below the melt temperaturethereof. In this way, a weak adherence of the coating layer on thetransfer element is achieved or sufficient, respectively.

According to one embodiment, a high lateral resolution is achieved bythe pressure based compaction of the coating layer at a temperaturewhich is above the glass transition temperature and below an uppertemperature, wherein the upper temperature is 30° C. above the glasstransition temperature. According to other embodiments, the uppertemperature is 5° C. above the glass transition temperature or, inanother embodiment, 15° above the glass transition temperature. By suchpressure based thermally assisted compaction fine-grained powder can bebuilt up with steep edges. The mechanical compaction assists inmaintaining the steep edges up to the pre-curing which allows a highlateral resolution in the coating layer. For example, according to anembodiment resolutions of above 400 dots per inch (dpi) or above 10 l/mmare achieved.

According to an embodiment, only a single coating layer is applied tothe transfer element/substrate. According to another embodiment, two ormore coating layers are applied on the transfer element, wherein a firstcoating layer of the at least two coating layers is applied on thetransfer element and a second coating layer is applied on the transferelement (and in particular over the first coating layer). Two or morecoating layers may require some effort in registration of the two ormore layers (in particular if the two or more layers includehigh-resolution images). On the other hand, applying the desired coatingthickness by two or more coating layers may facilitate the generation ofsteep edges. This is in particular the case if the first coating layeris compacted before the second coating layer is applied over the firstcoating layer. Compaction may include mechanical compaction (e.g.pressure induced) and/or thermally assisted compaction (e.g. temperatureinduced). Thermally assisted compaction includes heating the respectivecoating layer to a temperature at which during in the desired processingtime a flow of amorphous material occurs (wherein the temperature is inparticular in a temperature range in which the amorphous material is inits supercooled liquid state).

According to an embodiment, the first coating layer is pre-cured or atleast partly pre-cured before the second coating layer is applied overthe first coating layer. This may allow for stable steep edges of thecoating (which comprises the first coating layer and the second coatinglayer) even at large thicknesses, e.g. above a thickness of 50 μm.According to an embodiment, the pre-curing is performed such that ineach coating layer sufficient functional groups remain which can reactwith the neighboring coating layer. On the one hand this may be achievedby only a partial cure of the individual coating layers before applyingthe next coating layer, or by non-stoichiometric composition (e.g.excess of specific functional groups in the first coating layer andexcess of the complementary functional group, which reacts with thespecific functional group, in the second coating layer) or just by thefact that after curing still some functional groups are left based onthe increase of immobility during the curing process. Hence, in such anon-stoichiometric composition even if the component having the specificfunctional groups in the first coating layer is completely cured (i.e.no further reaction takes place) there will remain a portion of thespecific functional groups that react with the complementary functionalgroup in the second coating layer.

Further, by specific additives or by functionalization of mechanicalproperties of conventional toner components, e.g. charge control agents,an inter-particle adhesion among the particles of the powdery coatingmaterial may be improved, thus allowing steeper edges of the coatingmaterial (larger angles of repose) in the coating layer (i.e. before anycompaction, flow or partial cure is effected). Such measures may assistin achieving both, high-resolution and large thicknesses of the coatinglayer. For example, a resolution of 1000 dpi corresponds to a dot sizeof 25 μm. With a thickness of the coating layer of 50 μm thiscorresponds to an aspect ratio of 2:1. This in turn requires an angle ofrepose of more 76° to avoid coalescence of two dots separated by asingle dot size (25 μm). The influence of additives may be compared tosand. Dry sand has an angle of repose of about 35° wherein for wet sandan angle of repose close to 90° is possible.

A high angle of repose is preferred because the higher the angle ofrepose is (i.e. the closer the angle of repose is to 90 degrees andhence the steeper the edge of the coating layer is) the less is theeffect of ablation of the coating layer on an image depicted by thecoating layer.

In contrast to conventional powder coating, no pressurized air is usedas primary conveying medium in NIP methods. This allows for thin coatingthicknesses while still maintaining known properties of conventionalpowder coatings since in a NIP method no or only very low danger ofinclusion of microscopically small air bubbles exists. Nevertheless,compared to conventional NIP methods an oversized thickness of thecoating layer is necessary to achieve the typical properties of a powdercoating (e.g. long-term weathering resistance). For example, by a sandabrasion usually a certain thickness of the coating layer is abradedeach year which has to be provided in advance by a sufficient (initial)thickness of the coating layer.

According to an embodiment the coating material does not containdegassing agents. This is possible because according to an embodiment nopressurized air is used for applying the coating material to thetransfer element. Further, a compaction of the coating layer on thetransfer element has a degassing effect. Since the compaction of thecoating layer is performed on the transfer element, the pressure ofcompaction can be optimized in particular regarding compaction degreeand degassing separate from the application of the coating layer to thesubstrate. According to an embodiment, the compaction is performed atthe glass transition temperature of the uncured amorphous material(sometimes also referred to as Tg0) or in the vicinity thereof, e.g. ina temperature range the lower limit of which extends down to 20 Kelvinbelow the glass transition temperature and the upper limit of whichextends up to 15 Kelvin above the glass transition temperature [Tg0—20K; Tg0+15 K].

By using an amorphous material in the coating material it can beachieved that an initial adherence (without thermal treatment) among thepowder particles is higher than an initial adherence of the powderparticles on the transfer element. According to an embodiment theelectrostatic parameters of a printing device according to the hereindisclosed subject matter are respectively adapted. For example, if theprinting device comprises a transfer drum and an intermediate transferbelt, the voltage of the transfer drum and the transfer power of theintermediate transfer belt are adjusted accordingly.

In the following a printing process according to embodiments of theherein disclosed subject matter is described exemplary: First it isstarted the activation of the powder particles in the developer stationwith a system of screws and particles together with carrier getactivated by movement/friction. Then a (−) voltage is applied to themixing (step 3 below)

1. Charging: The whole surface of the image organic photoconductorroller (OPC) is uniformly electrically charged by the charging corona(−800 VDC) A LED light source is used in writing an electrostatic latentimage on the OPC.

2. Exposure: The print pattern is written in dots with LED light (−100VDC) and the OPC is discharged where light hits the surface. Anelectrostatic latent image is formed on the OPC.

3. Developing: Toners negatively charged (−500 VDC) are adhered to thelatent image on the OPC.

4. Transferring: The toners adhered to latent images are transferred tothe surface of the transfer roller positively charged ((+) 200-800 VDC)and then toner is transferred from transfer roller to the surface(Metal, MDF, Glass, Tiles, standalone transfer element)

According to an embodiment the heating device, which is configured forheating the coating layer on the transfer element before or during theapplication of the coating layer to the substrate, is a heatableelement, e.g. a heatable roller which is also referred to as fixationroller. Caking of part of the coating material on the heatable elementcan be avoided or at least be reduced by several measures. For example,one such measure is to induce viscous in flow in the coating material(e.g. by pressure and/or temperature). For example, flow of the coatingmaterials (and in particular of the powder particles) and hencecoalescence of the powder particles can be achieved by heating thecoating material into the supercooled liquid state above the glasstransition temperature Tg0 but (well) below a melt temperature Tm (ifsuch melt temperature exists). Another such measure is to partially curethe coating layer (e.g. by pressure, ultraviolet light, temperature(e.g. by infrared radiation, contact heating elements, etc.)). Anothermeasure and in accordance with a further embodiment, (further)compaction of the coating layer can be performed after inducing flow ofthe coating material before partially curing of the coating material.Another such measure is to provide a combination of elastomeric anddurable plastic effects, e.g. by combination of crystalline andamorphous binder materials in the coating material or by using purelyamorphous binder materials in the coating material.

According to an embodiment, at least one of an UV initiator and athermal initiator (e.g. a mixture of UV initiator and thermal initiator)in case of a resin with radical curing and/or an UV initiator in casethe resin can be cured by cross linkers (i.e. in case the resincomprises unsaturations).

By inducing viscous flow in the coating material and/or partial curingof the coating material a high mechanical stability of the coating layercan be achieved, which according to an embodiment can be a foil like(connected) intermediate state. Such a foil like intermediate state ofthe coating layer can reduce or avoid the caking on heatable elements.

Viscous flow of the coating layer and/or partial curing of the coatinglayer (and in particular a foil like intermediate state of the coatinglayer) also facilitates the handling of the transfer element since thecoating layer already has some stability against environmental impactsbut is not brittle as the fully cured duroplastic systems usually are.Brittleness could lead to a cracking off of the coating layer from thetransfer element.

Thereby inducing viscous flow at comparably high viscosities (i.e. inthe vicinity of the glass transition temperature) and in particular byavoiding a liquid state above the melt temperature Tm micro gas bubblescan be avoided. Further, by using amorphous binder materials in thecoating material the curing range can be extended over a largertemperature range without the detrimental effects on the lateralresolution of the coating layer. In this way, desirable properties ofconventional powder coatings can be achieved with the coating layerdescribed herein (e.g. ceiling, high-temperature resistance, weatheringresistance, long-term ultraviolet stability, wearing protection, beingfree from pinholes, wear based bleaching protection, outdoor capability,scratch resistance, resistance to solvents, diffusionreduction/diffusion barrier, etc.).

According to a further embodiment, for applying the coating layer to thesubstrate (e.g. before applying or during applying the coating layer tothe substrate) the temperature of the coating layer is increased to atemperature above a curing temperature of the coating layer so as topartially cure the coating layer before removal of the transfer element.In this regard it is emphasized that before removal of the transferelement the coating layer is only partially cured, e.g. by a suitabletime period during which the temperature of the coating layer ismaintained at or above the curing temperature. For example, according toan embodiment the partial curing of the coating layer before removal ofthe transfer element is performed by rapid heating of the coating layerto a temperature above the curing temperature and rapid cooling of thecoating layer after a short period of time.

Such a typical heating/cooling range could be between 10 K/min and 100K/min. However, the main aspect is that only partial curing happens.Such partial curing can be defined in that way that after this partialcuring still some reactions heat is given or consumed depending on thetype of reaction (endotherm or exotherm or combinations thereof). Also ashift of higher than 1-2° C. of the Tg measured with DSC with a heatingrate of 20 K/min of the coating is a good indication that only partialcuring has happened. Preferably based on the heat formation/consumptionof the reaction a partial curing of below 80%, even more preferablybelow 50% is chosen.

According to an embodiment, the rapid heating of the coating layer to atemperature above the curing temperature is performed after applicationof the coating layer to the transfer element but before the transfer ofthe coating layer to the substrate. A rapid heating of the coating layerto a temperature above the curing temperature (e.g. a shock-like(sudden) impulse heating) may also provide a gloss forming liquid phasebefore curing begins. By controlling the heating parameters the degreeof degassing, the ductileness/brittleness and hence the ability tohandle the coating layer during the transfer from the printing device tothe substrate is also controlled. In another embodiment theductileness/brittleness is also controlled in direct printing.

According to a further embodiment, the partial curing of the coatinglayer (or the rapid heating of the coating layer to a temperature abovethe curing temperature) is performed during applying the coating layeron the transfer element to the substrate. In this way, the coating layerand in particular an image represented by the coating layer has asufficiently high curing degree which ensures that a subsequent verticalposition in a curing oven does not adversely affect the quality of theimage/the lateral resolution of the coating layer. According to anembodiment, during the application of the coating layer to the substratethe substrate is in a horizontal position (i.e. the direction of gravityis perpendicular to the coating layer) or the substrate is at least notin a vertical position.

The rapid heating of the coating layer can be performed by any suitableheating device, e.g. an infrared radiator, a laser, etc. According to anembodiment, the heating device is configured for directly heating thecoating layer. According to a further embodiment, the heating device isconfigured for heating the coating layer indirectly, e.g. by heating thesubstrate.

The viscous flow and/or the partial curing of the coating layer mayimprove the fully cured coating layer on the substrate regardingresistance to abrasion, scratch resistance and long-term resistanceregarding solvents.

By the continuous coloring of the coating layer throughout the thicknessof the coating layer in particular in the case where the coating layerrepresents an image, an integrated bleaching protection for the appliedimage is achieved in outdoor applications. In known systems a thinundercoat is covered with a transparent thick protection layer e.g. byelectromagnetic brush (EMB, see e.g. http://www.emb-technology.com/). Incontrast, embodiments of the herein disclosed subject matter include theimage throughout the coating layer.

In this way, in an outdoor application the natural operation isfunctionalized and exposes continuously new color pigments in deeperpositions which are not bleached. Hence, the natural operation servesthe function of removal of bleached pigments. In an outdoor application,the abrasion is considered typically in the range of 1 μm to 2 μm peryear. Hence, it is possible to provide a wearing coat which maintains animage over several years even if subjected to sand erosion.

According to an embodiment, the transfer element is removable from thecoating layer application device. For example, according to anembodiment the transfer element is removed after applying the coatinglayer with the printing device. The transfer element may be shipped orstored separately. The transfer element may include protection featureslike soft packaging made of polymers or other foil layers between fortransport and storage of the coating layer on the transfer element.Preferably the packaging material is chosen in a way that during thestorage time and conditions no transfer of materials coming out of thepackaging material to the coating happens. Special attention is givenhere to the use of materials not including a high content of mobileplasticizers which could reduce the Tg of the coating. Also thetransport should be done below Tg, especially if some pressure is givento coatings. The aforesaid applies as well for the final cured printingon the substrate.

A conventional NIP transfer method adapted to embodiments of the hereindisclosed subject matter may provide one or more of the followingfeatures: first, the heating rate may be precisely controlled; second, arapid heating of the coating layer to a temperature above the curingtemperature may be provided. Final curing (which may be performed at adifferent place) may provide properties which are typical for powdercoatings, in particular regarding adherence and sealing.

Since the glass transition temperature of the amorphous material is ameasure for the dynamics of processes in the coating material, a lowglass transition temperature may provide for properties known frompowder coatings, e.g. diffusion increasing properties and the desiredpinhole free state of the cured coating, within a short curing time. Inconnection with the possible expression of residual micro gas bubblesduring (or before) the curing process a pinhole free film is formedwhich exhibits the desired diffusion reducing properties.

Besides the thermal treatment also the chemical composition of thecoating material can assist in providing the desired properties of thefinally cured coating layer. For example, it was found that a largethickness and a good lateral resolution can be achieved (and optimized)by including a charge control agent in the coating material, e.g. in anamount in a range between 1 to 5 w-% of the coating material. Inparticular advantageous has proven salicylic based, especially a zinksalicylic acid based charge control agent.

Diffusion reducing/preventing properties of a coating layer dependessentially on two parameters: the diffusion rate of the material andthe thickness of the coating layer. According to embodiments of theherein disclosed subject matter a large thickness of the coating layeris achieved which provides (at a given diffusion value, e.g. for water,oxygen, etc.) good diffusion reducing properties. By adding a suitableamount of charge control agent an optimum of both parameters diffusionrate and coating layer thickness may be achieved, in particular by arelatively small amount of charge control agent of 1% to 5%.

In particular by the zinc salicylic acid based CCA additional advantagesare achieved: good outdoor stability (keeping the outdoor stabilityknown from powder coating systems by choosing the right CCA), goodconsistent network-forming a behavior, and high color density. Foroutdoor application it was surprisingly found that about 1% or even morelike 2% was necessary to get the best color density. Additionallysilica, preferably with a particle size between 1 and 100 nm, mostpreferably between 5 and 70 nm was found to increase the chargingproperties of the here mentioned thermoset materials.

According to an embodiment, the use of suitable CCAs provides for arapid latent image generation during the printing. In this way, a highthroughput in the printing process is achieved. According to anembodiment, a latent image change within less than one second can beachieved with a coating layer thickness of more than 5 μm, in particularmore than 10 μm and in particular up to 100 μm, e.g. a thickness between5 μm and 8 μm.

Further, the addition of particulate material, the particles of whichhave (and preferably maintain) a shape which deviates from a sphericalshape may assist in providing desired properties of the finally curedcoating layer, e.g. in providing a high lateral resolution in thecoating layer. Also a high surface roughness of the particles may assistin providing such desired properties. Such particulate material may onlyserve one function or may serve a further function as described herein.For example, the particulate material may also serves the function of acharge control agent. In this regard, the zink salicylic acid basedcharge control agent mentioned above also improves the mechanicalproperties of the uncured or partially cured coating layer and helps toachieve a high lateral resolution in the coating layer. Without beingbound to theory it is assumed that this advantageous property is due tothe elongated (rod-like) shape of the particles and/or the surfaceroughness of the particles.

It is noted that the term “curing” in the sense of the herein disclosedsubject matter means in particular curing by reaction of one or more(e.g. two or more) binder materials with itself and/or each other (e.g.initiated by thermal radical initiators for unsaturated systems or byone or more binder materials and additional curing agents (e.g.polyester with epoxy resins, primid curing systems (β-hydroxyalkyl-amide(HAA)), etc.). According to an embodiment, including thermal curingsystems or pure thermal curing systems is preferred.

According to an embodiment, after applying the coating layer to thetransfer element (or to the substrate in a direct print method), thecoating layer is subjected to a further treatment according toembodiments of the herein disclosed subject matter, e.g. inducingviscous flow in the coating layer, partially curing the coating layer,compaction of the corporate coating layer (in particular by exertingpressure on the coating layer).

According to an embodiment, by suitable controlling of the partialcuring the retention time in the gel state of the coating material issufficiently reduced so that notwithstanding the continuous coloringthroughout the coating layer a high lateral resolution is achieved butno blurring effects reduces the lateral resolution. For example, in afurther embodiment, a high pre-curing temperature is used but for ashort time period which triggers the vitrification process by curing(change of alpha) such that a viscous flow is reduced or prevented and alater handling during application of the coating layer to the substrateis facilitated, for example by reduced tendency of the coating layer toplastic deformation. This process could be supported by radiation curinglike UV and/or electron beam.

In an embodiment of the aforementioned principle the impulse likeheating of the coating layer is performed such that after the coatinglayer has been brought into contact with the substrate the temperatureof the coating layer is increased to a temperature above the curingtemperature for a short time such that due to the following rapidcooling a partial vitrification occurs such that no negative blurring isnoticeable. Further, in such an embodiment the point in time at whichthe transfer element is removed from the coating layer can be optimizeddepending on the application and the requirements. According to anembodiment, the adhesion of the coating layer on the substrate at atemperature which is in the vicinity of the glass transition temperatureor slightly above the glass transition temperature is good enough suchthat the transfer element can be already detached from the coatinglayer. In this way, the gloss of the coating layer may be optimized.Further, the transition free attachment of coating layers may befacilitated. According to an embodiment, by the temperature profile(rapid heating of the coating layer to a temperature above the curingtemperature) the adherence between the coating layer and the coatingelement is reduced (e.g. by suitable conditioning of the transferelement) such that the peeling off of the coating layer from thetransfer element is facilitated. According to an embodiment asacrificial layer is provided on the transfer element which facilitatesthe peel off. According to an embodiment, after application of thecoating layer and before removal of the transfer element the sacrificiallayer can be altered in its properties (e.g. by heating) such thatthereafter the peel off is facilitated. According to an embodiment, thesacrificial layer is destroyed during the final curing. For example,during the final curing the sacrificial layer may evaporate or outgas.

According to an embodiment, viscous flow at a temperature where theuncured coating material is in its glassy state (below its glasstransition temperature) is assisted by exerting pressure on the coatinglayer on the transfer element. According to an embodiment, the pressureon the coating layer is exerted by a roller. For example, if thetransfer element is a transfer drum, the pressure may be exerted by aroller pressing in a direction against the transfer drum.

In a further embodiment, the coating material is functionallysupplemented, e.g. by suitable choice of polymers, color pigments ordyes, that a long-term stable color fastness and ultraviolet (UV)resistance is achieved. By using of polyester derivatives an enhancedultraviolet resistance (e.g. compared to epoxy variants) in the finalproduct but also a simple thermal fixation in the electrophotographic orthermal NIP process may be achieved. Alternatively to this acrylic,F-polymer or urethane based coatings can also achieve a very goodweather stability.

At high temperatures (above 200° C.) conventional powder coatings havethe tendency to significantly change the color at least in criticalcolor regions and to lose the glossy appearance due to thermal attack onthe coating surface. By providing these colors as coating materialaccording to embodiments of the herein disclosed subject matter due tothe amorphous component and the resulting controllability and deepercuring temperatures such problems can be avoided.

According to an embodiment a color gradient is formed in the coatinglayer, wherein the color changes in a direction perpendicular to thecoating layer. According to an embodiment, the coating layer (e.g. onthe transfer element) is provided as an image comprising one or moredifferent colors, in particular more than two different colors, whereinthe image is different at different depths of the coating. For example,according to an embodiment the change in the image may be a gradualchange, e.g. resulting from a shallow edge of a coating layer. Accordingto a further embodiment, the change in the image may be stepwise. Such astepwise change in the image of the coating (e.g. change from an upperimage to a lower image in a direction from a surface of the coatingtowards the substrate) may be realized by providing two differentcoating layers on top of each other wherein the different coating layersshow different images. In particular a stepwise change in the image at acertain depth provides the possibility of exposing the lower image afterabrasion of the upper image. In particular the lower image may includehuman readable or machine readable portions (e.g. symbols or charactersindicating e.g. the remaining thickness of the coating).

Once transferred to the substrate and subjected to abrasion, differentimages at different depths of the coating may indicate the remainingthickness of the coating. This may be used as an indication as to whenan after treatment of the coating is necessary. Such features can alsobe used to detect missing coating spots when the coating has also aprotection function against corrosion (e.g. fluorescent coating belowwhich shine through when the above coating is not completely closed).

According to an embodiment, the fact that an uncured or partially curedcoating layer provides a good adhesion to a further uncured or partiallycured coating layer is used for providing additional functionality. Forexample, the transfer element may already comprise a first coating layerwhen a second coating layer is applied to the transfer element.Likewise, the substrate may already comprise an undercoat when one ormore coating layers on a transfer element are applied to the firstcoating layer. In this regard it is noted that the undercoat may begenerated by conventional powder coating or other conventional coatingtechnologies or may be a coating layer in the sense of the hereindisclosed subject matter. It should be emphasized that with thisembodiments of the herein disclosed subject matter a special benefit isgiven by the fact that a high resolution printing can be build up whichfollows the same chemistry like conventional coatings like powdercoatings and therefor a very good compatibility according to adhesion,chemistry, thermal expansion and so on is given. This opens the use ofhigh quality printing in many industrial applications which were notachievable up to now.

According to a further embodiment, by suitable selection and compositionof charge control agents, polymers, color pigments and dyes, and inparticular amorphous components as well as by suitable control of thecuring degree a high temperature stability of the coating layer can beachieved like with silicone based resin systems. In the use ofconventional toners or crystalline coating materials in the followingproblems are known: At high fixing temperatures of the toner, inparticular in case of a relatively thick toner layer, deposits may formon the fixation roller due to the thermoplastic properties of the toner.Further, for example PANTONE® Rhodamine Red, Purple, Blue 072, ReflexBlue as well as HKS® 27, 33 and 43 are known to be prone to causeproblems due to the low temperature stability of its pigments duringfixation of the toner. Accordingly in conventional toner systems usuallyit is attempted to replace the pigments of low stability with morestable pigments of similar color.

In accordance with embodiments of the herein disclosed subject matter, amultistage curing, includes a partial curing of the coating layer at lowtemperatures and/or rapid partial curing at high temperature. Suchprocessing may assist in avoiding problems due to low temperatureresistance of color pigments. In particular the application of thecoating layer to the substrate can be divided into two stages: thermalstart of the fixation of the coating layer on the substrate (forsubstrates with high thermal conductivity (e.g. metals) a (shocklike)temperature impulse may be achieved). According to an embodiment, thethermal start of the fixation is performed at a temperature which isabove the curing temperature which transfers the coating layer into agelled or soft state which promotes a spontaneous adhesion on thesubstrate and facilitates the detachment of the transfer element. In thesubsequent final curing a different temperature profile may be imposed,e.g. so as to achieve a glossy surface and a high quality finish.

According to an embodiment, partial curing of the coating layer on thetransfer element is performed by non-thermal curing mechanisms. Forexample, according to an embodiment the non-thermal curing mechanism isa partial curing by ultraviolet radiation. Non thermal curing mechanismshave the advantage that curing and viscous flow of the coating materialcan be controlled separately.

According to a further embodiment, partial curing in the sense of theherein disclosed subject matter includes different curing degrees overthe thickness of the coating layer. For example, according to anembodiment a first portion of the coating layer which is facing thetransfer element is cured to a higher degree than a second portion (e.g.a free surface portion which is to be attached to the substrate) of thecoating layer which is opposite the first portion. In this way, theadherence of the coating layer on the transfer element may be reducedwhile maintaining good adhearing properties of the free surface of thecoating layer which is facing away from the transfer element and whichis intended to be attached to the substrate and additionally theresolution then at the top of the coating on the substrate may thereforebe improved.

Compared to conventional powder coatings the thickness of the coatinglayer is reduced. However, surprisingly such relatively thin coatinglayers (compared to the thickness of conventional powder coatings)applied according to embodiments of the herein disclosed subject matterprovide still the desired characteristics of conventional powdercoatings (in weathering protection and resistance against chemicals andeven corrosion protection can be achieved in some embodiments). Withoutbeing bound to theory it is assumed that the reason for the surprisinglygood performance of the coating layer according to embodiments of theherein disclosed subject matter is in particular at least one of (i) thecompaction of the coating layer on the transfer element, (ii) theinitiation of viscous flow of the coating layer (i.e. the viscous flowof the coating material in the coating layer) and (iii) a reducedparticle size of the coating material compared to conventional powdercoating materials.

Due to the possibility to provide the desired protection with arelatively small thickness of the coating layer embodiments of theherein disclosed subject matter provide a cost efficient coating alreadydue to material savings.

According to an embodiment, a coating on the transfer element isprovided by one or more coating layers as described herein. According toan embodiment, a first coating layer of the one or more coating layersis subjected to viscous flow and/or partial curing before a secondcoating layer of the one or more coating layers is applied on thetransfer element above the first coating layer. According to a furtherembodiment, one or more coating layers are applied to the transferelement without subjecting the one or more coating layers to viscousflow and/or partial curing. In this case, the coating comprising one ormore coating layers may be subjected to viscous flow and/or partialcuring afterwards.

According to an embodiment, the application of the one or more coatinglayers on the transfer element is performed by a single printing device.In particular, in such a case the one or more coating layers may beapplied subsequently on the transfer element by the same printingdevice, e.g. the transfer element may run through the printing deviceone or more times.

According to a further embodiment, the application of the one or morecoating layers are performed by a respective number of printing devices(i.e. one or more printing devices).

Providing the coating on the transfer element by one or more coatinglayers allows for a higher resolution because the effect of the angle ofrepose is reduced.

By the multilayer structure of the coating the inherent stability of thecoating to be transferred may be increased and therefore the mechanicalrequirements for the transfer element may be reduced. For example,according to an embodiment a micro perforated transfer element (e.g. amicro perforated transfer film) may be used as a transfer element. Bymicro perforation the adherence of the coating on the transfer elementand/or a surface structure of the coating after application to thesubstrate may be controlled.

Further, increased inherent stability of the coating to be transferredmay be used to reduce processing requirements for the transfer of thecoating on the transfer element (e.g. maximum temperature change duringtransfer (may lead to mechanical stresses), minimum angle of bending ofthe coating (may result in detachment of the coating from the transferelement), minimum temperature (too low temperatures may increasebrittleness of the coating)).

According to an embodiment, the coating material comprises at least oneamorphous component (e.g. an amorphous binder) without compounds (e.g.additives) which are typical for conventional toners, such as bisphenolA and epoxy resins. Due to the renouncement of these additives a coatingof substrates is possible which may end up in the metabolism of a humanbeing (bisphenol A) or which relate to outdoor applications withoutfurther protection mechanisms (epoxy).

Presently bisphenol A as plasticizer is subjected to criticism becauseit is assumed that this compound has a negative influence on thehormonal system, reproduction disorder and developmental disorder. Epoxybased applications without additional protection are not suitable foroutdoor applications because they do not exhibit weathering stability.

By using a transfer element coatings may be applied to substrates whichcannot be coated in a direct method (e.g. because the printing systemwould be too large or would be not available at a particular(peripheral) location. A typical example would be a can with anadvertisement or a notice on its inside surface (e.g. “please do notdischarge”, “please recycle”) or thermochromic coatings which areapplied to a frying pan and indicate the working temperature.

According to an embodiment, by partial curing before application to asubstrate the coating is transferred into a film-like state which allowsa transfer without transfer element (in this case no transfer element isneeded for transferring the coating to the substrate). Nevertheless, byfinal curing of the coating on the substrate the full adherence of thecoating on the substrate is provided. Whether or not a coating hassufficient inherent stability to be transferred without transfer elementmay depend on the thickness of the coating and the material parameters(e.g. elastic modulus, hardness, etc.) of the partially cured coating.

According to an embodiment, the surface of the transfer element, onwhich the coating is applied, is configured such that the interfacialenergy between the transfer element and the coating is temperaturedependent such that the adherence of the coating on the transfer elementbecomes smaller at higher temperatures. Hence at elevated temperatures,during the contact of the coating and the substrate, the adhesionbetween the transfer element and the coating is smaller than at lowtemperatures during the transfer from the printing device to thesubstrate. Hence, the peel off of the transfer element is facilitatedwhile on the other hand during the transfer from the printing device tothe substrate the coating is securely adhered to the transfer element. Arespective configuration of the surface of the transfer element may berealized by providing the transfer element with a wax, e.g. a Teflonbased wax, which defuses to the surface at elevated temperatures thusreducing the adherence of the coating on the transfer element. Also theuse of different electrostatic charging of the transfer element duringthe transfer of the coating to the transfer element and/or the transferfrom the transfer element to the substrate is an option according to theinvention. Further, according to an embodiment, charging of thesubstrate during applying of the coating layer to the substrate isperformed, in particular in a direct printing application where acoating layer is directly applied to a substrate.

According to a further embodiment, the transfer element is covered witha nonstick agent. The nonstick agent facilitates removal of the transferelement from the coating after applying the coating with the transferelement to the substrate.

According to an embodiment, the coating material comprises a powderysolid state material which remains solid over the entire temperaturerange used for processing and curing of the coating layer. As is knownfrom early work of Einstein (A. Einstein, “Eine neue Bestimmung derMoleküldimensionen”, Ann. d. Physik, 19(4):289, 1906) solid particlesdispersed in a viscous liquid increase the viscosity of the viscousliquid. Hence, for a given polymer the (temperature dependent) viscositymay be adjusted by the powdery solid state material. Hence, for examplethe viscosity of the coating material at the curing temperature may beadjusted so as to provide sufficient viscous flow within the respectiveprocess time window while on the other hand providing a desired lateralresolution.

According to an embodiment, a final curing of the coating layer on thesubstrate is performed in a conventional curing oven. According to afurther embodiment, final curing is performed or at least initiated byultraviolet (UV) radiation. For UV curing the thickness of the coatinglayer according to embodiments of the herein disclosed subject matter iswell suited. While in a conventional powder coating UV curing is oftendifficult due to the large thickness which leads to an over curing atthe surface (and hence to a danger of brittleness) or the radiationdensity in greater depth is too low for a uniform curing process (or theheating over the volume is not sufficiently uniform) or for achievecuring during the integral “energy density*time”. Because according toembodiments of the herein disclosed subject matter thinner coatinglayers may achieve similar or identical properties as comparativelythicker conventional powder coating layers, thinner coating layers maybe applied which avoided or at least reduced problems of conventionalpowder coating layers in ultraviolet curing. Further, pressure rollers(corresponding to fixing rollers of conventional NIP systems) may beused to compact the coating layer which again allows for a thinnercoating layer compared to conventional powder coating systems.

According to an embodiment, the composition of the coating material isadapted to the desired thickness of the coating layer on the substrate.For example, according to an embodiment, a larger mean particle diameterof powdery coating material may be used for thicker coatings. This is inparticular suitable, for relatively thick coatings (in particular if thethick coating is applied in a single coating layer) and if noexceptional high demands on the resolution are made. Further, an angleof repose of the coating material may be adapted by suitable additives.Hence, the desired angle of repose may be achieved while considering theadhesion values in the NIP process and the transport time between theprinting and the initiation of partial curing/viscous flow. Inparticular bigger particles might improve the haptic effect of thecoating.

According to another embodiment, also for a larger thickness a smallmean particle diameter of the coating material may be used for achievinga high resolution. In combination with the control of a steeper edge onboundaries, e.g. color boundaries in the coating layer thus a higherresolution may be achieved. In particular with a coating layer thicknessof over 150 μm with a particle diameter of below 30 μm on the one hand ahigh resolution is achieved while on the other hand a high thickness ofthe coating layer after the curing is achieved.

FIG. 3 shows a cross-sectional view of a coating layer applicationdevice 200 according to embodiments of the herein disclosed subjectmatter.

According to an embodiment, the coating layer application device 200comprises a transfer element support 202 for supporting a transferelement 204 comprising a coating layer 206. The coating layer is curableand comprises an amorphous polymer. In accordance with an embodiment,the coating layer 206 is a thermosetting polymer composition which wasapplied to the transfer element 204 in the form of a powdery coatingmaterial. The coating layer application device 200 further comprises asubstrate support 208 for receiving a substrate 210 onto which thecoating layer 206 shall be transferred. In accordance with anembodiment, the transfer element support 202 and the substrate support208 are operable to bring the coating layer 206 in contact with thesubstrate 210. For example according to an embodiment this is effectedby an actuator 212. According to an embodiment, the actuator 212 isoperable to drive the transfer element support 202 with the transferelement 204 and the coating layer 206 towards the substrate 210 and tothereby bring in the coating layer 206 and the substrate 210 intocontact. The actuator 212 may be further operable to drive the transferelement support 202 so as to exert a pressure on the coating layer 206in order to press the coating layer 206 onto the substrate 210.

The coating layer application device 200 further comprises a heatingdevice 214. According to an embodiment, the heating device 214 isconfigured to heat the substrate 210 (e.g. via the substrate support208). At least by bringing the coating layer 206 in contact with thesubstrate 210, also the coating layer 206 is heated by the heatingdevice 214. According to a further embodiment the heating device isconfigured to heat the transfer element support 202 (heating device 215,shown as alternative embodiment in dashed lines in FIG. 3). Hence, ifthe transfer element 204 with the coating layer 206 is received by thetransfer element support 202, the coating layer 206 is heated by theheating device. According to an embodiment, a control device 216 isprovided for controlling in particular the heating device 214, 215. Tothis end, the heating device 214, 215 is controllably connected to thecontrol device 216, as indicated at 218 for the heating device 214.According to a further embodiment, the control device 216 is alsocontrollably connected, indicated at 218, to the actuator 212 in orderto coordinate the operation of the actuator 212. According to anembodiment, the control device comprises a processor device 217 which isconfigured for executing a program element which is configured forimplementing a control according to one or more embodiments of theherein disclosed subject matter. It is noted that the control device maybe configured in any suitable way to implement such embodiments, e.g. inan open loop control configuration or in a closed loop controlconfiguration.

After attaching the coating layer 206 to the substrate 210, which isaccording to an embodiment performed by suitably heating the coatinglayer 206, in accordance with an embodiment the transfer element 204 isremoved from the coating layer 206 (i.e. is separated from the coatinglayer 206). Such a removal of the transfer element 204 from the coatinglayer 206 may be affected by the actuator 212 which according to anembodiment is operable to retract the transfer element support 202 andhence the transfer element 204 from the coating layer 206 attached tothe substrate 210.

According to an embodiment, the control device 216 is configured forcontrolling the heating device so as to maintain the temperature of thecoating layer 206 below a first temperature before the removal of thetransfer element 204 from the coating layer 206, wherein at the firsttemperature the uncured coating material is in its supercooled liquidstate or in its glassy state. As described in detail herein, this mayallow in particular for maintaining a high resolution of an image of thecoating layer 206. In another view the above corresponds to controllingthe temperature of the coating layer 206 so as to maintain thetemperature of the coating layer 206 within a first temperature rangebefore the removal of the transfer element 204 from the coating layer206 wherein within the first temperature range the uncured coatingmaterial is in its supercooled liquid state or in its glassy state.

According to a further embodiment, the control device 216 isalternatively configured to partially cure the coating layer 206 duringthe contact of the coating layer 206 and the substrate 210 by increasingthe temperature of the coating layer 206 to a second temperature at orabove a curing temperature of the coating layer 206. According to oneembodiment, the second temperature is at or above a curing temperatureof the uncured coating material.

According to an embodiment, the coating layer application device 200comprises an energy transfer device 220, e.g. in the form of a radiationdevice which is configured for emitting radiation 222 towards thecoating layer 206. The energy transfer device 220 may be configured topartially cure (or assist in the partial curing of) the coating layer206 during the contact of the coating layer 206 and the substrate 210(e.g. if the radiation 222 is ultraviolet radiation), even if thetemperature of the coating layer 206 is maintained below the firsttemperature.

According to a further embodiment, the energy transfer device 220 may beconfigured for emitting the radiation 222 in the form of infraredradiation. In other words, the energy transfer device 220 may beconfigured as heating device in the sense of the herein disclosedsubject matter to heat the coating layer 206 to an elevated temperature,e.g. to the first temperature or, in another embodiment, to the secondtemperature. In accordance with an embodiment, the energy transferdevice 220 is controllably coupled, indicated that 218, to the controldevice 216.

It is noted that although more than one heating device 214, 220 (andeven 215 as alternative embodiment) is shown in FIG. 3, according toother embodiments only a single heating device configured for heatingthe coating layer 206 on the transfer element (e.g. only 214 or 215 or220) may be provided.

According to an embodiment, the transfer element support 202 comprises aflat support element which supports the transfer element 204 and thecoating layer 206 thereon over the entire surface of the coating layer206. According to a further embodiment, the transfer element support 202comprises a support element which conforms to the shape of thesubstrate. According to a further embodiment, the transfer elementsupport 202 comprises a roller which supports a portion of the transferelement 204 (and which may exert a pressure on the portion of thetransfer element 204) at a particular time. In such an embodiment, inwhich the transfer element support comprises a roller, the (entire)transfer element 204 is supported (and pressed towards the substrate) bymoving the transfer element 204 past the roller of the transfer elementsupport.

It is noted that the above description with regard to FIG. 3 is given byreferring to a coating layer 206. It should be understood that withinthe scope of other embodiments this description may be considered asreferring to a layer package comprising at least one layer wherein oneof the at least one layer is the coating layer 206.

FIG. 4 shows a coating layer application device according to embodimentsof the herein disclosed subject matter.

According to an embodiment, the coating layer application device 300comprises a printing device 301. According to an embodiment, theprinting device 301 comprises at least one printing unit, e.g. threeprinting units 224, 225, 226. According to other embodiments, more orless printing units (e.g. four printing units) may be provided.According to an embodiment, at least eight printing units may beprovided (e.g. for cyan, magenta, yellow, key (black), white,transparent, metallic effect, at least one spot color). For example,according to an embodiment coating materials of different colors (e.g.for cyan, magenta, yellow, key (black), white, transparent, differentmetallic effects and colors and different spot colors for each type ofcoating (e.g. Indoor, Outdoor, . . . )) may be provided and for eachsuch coating material an individual printing unit may be provided. Asthis is optional, it should be understood that according to anembodiment two or more printing units may comprise the same coatingmaterial. It is noted that generally any reference to different colorsmay be considered as a reference to different coating materials.

For the avoidance of doubt it is mentioned that independently of thetype of printing machine and number of printing units any suitable coloror set of colors can be used, in particular CMYK, white, transparent,effect colors and/or so called spot colors, within the frame of theherein disclosed subject matter.

According to one embodiment, each printing unit 224, 225, 226 isconfigured for applying its coating material to the transfer element byprinting to thereby form the coating layer. According to one embodiment,at least some of the coating materials (which may be referred to asimage forming coating materials) are each applied only to certainportions of the transfer element to thereby combine to a common image.In this sense, at least some of the coating materials (the image formingcoating materials) together form a single coating layer 206. Accordingto an embodiment the transfer element 204 is moved past the at least oneprinting unit 224, 225, 226 and hence the different coating materialsare applied subsequently to the transfer element 204 (and in particularto a surface 205 of the transfer element 204), by the different printingunits 224, 225, 226. In this regard, the surface 205 forms a targetsurface of according to the herein disclosed subject matter. As in aconventional NIP device, such as a conventional color laser device, thisrequires an appropriate registration of the image portions applied bythe individual printing units. The movement of the transfer element 204and the control of the printing device or the at least one printing unit224, 225, 226 is controlled by control device 216 which is controllablyconnected to the respective devices.

According to an embodiment, each printing unit is an electrostatic (andin particular an electrophotographic) printing unit, which include anorganic photoconductor 227 (OPC) which is first uniformly electricallycharged, a light source (e.g. LED or laser source) is used for writingan electrostatic latent image on the OPC and the thus exposed OPC isdeveloped with a coating material 237 according to embodiments of theherein disclosed subject matter. Thereafter, the coating material 237 istransferred to a first transfer element 228 (intermediate transferelement), e.g. by applying a suitable electrical field, to thereby formthe coating layer 206 on the first transfer element 228. According to anembodiment, the coating layer 206 is then transferred to the transferelement 204 (which may be referred to as second transfer element 204).According to an embodiment, the coating material 237 is located in acartridge 239. According to an embodiment, for each type of coatingmaterial to be provided (to be applied to the transfer element 204), aseparate cartridge 239 is provided. According to an embodiment, to eachprinting unit 224, 225, 226 a cartridge is associated (e.g. a separatecartridge is provided). In order to not obscure FIG. 4, exemplarily acartridge 239 is shown only for one printing unit 224 of the printingunits of the printing device 301.

According to other embodiments, a printing unit does not include a first(intermediate) transfer element, as described with regard to FIG. 11.Accordingly, in such an embodiment, the printing units 224, 225 226 donot comprise the first transfer element 228. Rather, the coatingmaterial is applied from the OPC 227 to the transfer element 204(indirect printing) or directly to the substrate (direct printing).

According to another embodiment, the coating material is applied fromthe OPC 227 to the first transfer element 204 and from here to thesecond transfer element 204 (indirect printing) or to substrate (directprinting). According to an embodiment, the transfer element is a foil,paper, a belt, etc. in both cases.

Instead of two or more individual printing units for each color/coatingmaterial, a common printing unit which is configured for applying two ormore colors/coating materials to the transfer element may be provided.

According to an embodiment, the coating layer application device furthercomprises an energy transfer device 229 being configured fortransferring energy 230, e.g. in the form of radiation into the coatinglayer 206 on the transfer element 204 before the contact of the coatinglayer 206 and the substrate (not shown in FIG. 4). The energy may beheat. For example, according to an embodiment the radiation is infrared(IR) radiation.

According to an embodiment, the energy transferred into the coatinglayer 206 results in viscous flow in the coating layer 206. Inparticular, according to an embodiment the energy transferred into thecoating layer 206 is configured so as to cause viscous flow of at leastportions of the powder particles of the coating material which forms thecoating layer 206 at this stage. According to an embodiment, the viscousflow in the coating layer 206 occurs at least upon application ofpressure on the coating layer 206. To this end, according to anembodiment a compaction device 232 is provided configured for compactingthe coating layer 206 on the transfer element 204 before the contact ofthe coating layer 206 and the substrate (not shown in FIG. 4). Accordingto the embodiment, the compaction device 232 comprises a roller 234which is pressed against the coating layer 206, resulting in a pressingforce 236 in a direction towards the coating layer 206, as shown in FIG.4. According to an embodiment, in a conveying direction of the transferelement 204 (or the substrate in direct printing) the compaction device232 (or in particular the roller 234 thereof) is located after theenergy transfer device 229, as shown in FIG. 4. According to anembodiment, in a conveying direction of the transfer element 204 (or thesubstrate in direct printing) the roller 234 may be located before theenergy transfer device 229.

The transfer element support and the substrate support as well as theheating device (embodiments of which are shown in FIG. 3) are indicatedby the device 238 in FIG. 4.

It is noted that, although the coating layer application device 300 inFIG. 4 includes both, the device 238 (which includes the transferelement support, the substrate support and the heating device) and theprinting device 301, according to another embodiment, the printingdevice 301 may be a separate device which located at a location which isgeographically different from the location where the device 238 islocated. In such a case, the coating layer application device may notinclude the printing device 301. It should be understood that, e.g. ifthe printing device 301 and the device 238 located at differentlocations, each of the two devices 301, 238 (or any other device, e.g. acuring device) may have a separate control device. According to anotherembodiment, the two devices 301, 238 share the same control device 216,as shown in FIG. 4.

It is further noted, that besides the printing units 224, 225, 226 theprinting device may include further devices which act on the coatinglayer 206, for example the energy transfer device 229 and the compactiondevice 232. According to a further embodiment, the coating layerapplication device 300 includes further devices 229, 232 which act onthe compacting layer 206.

According to an embodiment, the transfer element 204 is foil-like orbelt-like and may in particular be a transfer foil as shown in FIG. 4.The transfer foil may be moved at constant speed as indicated by thearrow 240 in FIG. 4. According to an embodiment, the transfer element204 is a continuous transfer element, e.g. a continuous belt whichextends between two deflection pulleys. According to another embodiment,the transfer element is capable of being rolled up. For example,according to an embodiment the transfer element is provided on a supplyroll and is, after application of the coating layer, again provided as aroll, e.g. an intermediate product roll. There intermediate product rollof transfer element with the coating layer thereon may be stored orshipped for further use in a coating layer application device accordingto embodiments of the disclosed subject matter.

According to an embodiment, the transfer element 204 having the coatinglayer 206 thereon is removable from the coating layer applicationdevice. To this end, the transfer element and the coating layer thereonmay be provided in any suitable shape, e.g. in the form of a played, afoil or a roll (e.g. a rolled-up foil).

FIG. 5 to FIG. 8 illustrates different stages of a printing methodaccording to embodiments of the herein disclosed subject matter.

According to an embodiment and as shown in FIG. 5, the whole surface ofthe organic photoconductor 227 (OPC) is uniformly electrically chargedby a charging corona (e.g. −800 V DC). Some of the negative chargesshown in FIG. 5 are indicated at 242.

Thereafter, exposure of the OPC 227 is performed with a suitableradiation 244, e.g. LED light or laser light. The OPC 227 is dischargedwhere the radiation 244 hits the surface. In this way, and anelectrostatic latent image 246 is formed on the OPC 227, as shown inFIG. 6.

Thereafter, powdery coating material 248 according to embodiments of theherein disclosed subject matter is negatively charged (−500 V DC) andadhered to the latent image 246, as shown in FIG. 7. Negative chargesare again indicated at 242.

Thereafter the powdery coating material 248 is transferred to thetransfer element 204 which is positively charged to this end. Positivecharges are indicated at 250. Thus the powdery coating material 248forms the coating layer 206 (or forms part of the coating layer 206) onthe transfer element 204 and resembles the electrostatic image 246 onthe OPC.

It should be understood that FIG. 5 to FIG. 8 illustrate only theprinciple of an embodiment of a printing device. For example, while FIG.5 to FIG. 8 show flat surfaces of the OPC 227 and the transfer element204, any of these surfaces may also be curved (e.g. may form part of aroller). Further, it is noted that for positive charging systems (e.g.depending on the charge control agent) the voltages may be inversed(e.g. the OPC and/or the powdery coating material may be positivelycharged).

FIG. 9 illustrates a layer package and in particular a part of a coatinglayer according to embodiments of the herein disclosed subject matter.

For a powdery coating material, the application of the powder with alarge thickness 252 does not result in ideal edges but, according to anembodiment, rather in tapered edges 254 which form an angle 258 which isless than 90 degrees with the surface 256 of the transfer element 204.For example, according to an embodiment the angle 258 is in a rangebetween 60 degrees and 85 degrees. Since according to an embodiment theprinting device is a digital printing device, an image transferred tothe transfer element 204 includes a plurality of dots. Hence a gap 260may be formed between two adjacent dots 264, 266. This gap may bereduced by pressure, e.g. if a further coating layer 207 is applied,indicated by a further dot 264-1 in FIG. 9. It is noted that the dot 264and the dot 264-1 form part of a layer package (indicated at 274)according to embodiments of the herein disclosed subject matter.Further, a roller may be used to compact the coating layer. Further, atleast during curing the coating material at high temperature the coatingmaterial may level out and the gap 260 may fill. According to anembodiment, dots may be printed with the same or a different coatingmaterial, indicated by dots 264, 266. In such a case, a void betweendots 264 of a first coating layer may be filled with a dot 266 of asecond coating layer (e.g. coating material of a different color,indicated by dashed line 262 in FIG. 9). Due to the tapered edges, thewidth of the gap 260 is different at different heights h1, h2 of thecoating layer. Hence, at h1 the width of a first dots 264 made from afirst coating material 248 is smaller than the width of a second,adjacent dots 266 made from a second coating material 268 which isapplied to the transfer element 204 after the first coating material248. The vertical dashed lines 270 in FIG. 9 indicate the size 272 of adot as printed. Since the width of the dots 264 of the coating layer 206changes with the height through the coating layer, the resulting imagechanges if the thickness of coating layer is reduced, e.g. from h1 to h2(e.g. by abrasion).

In accordance with an embodiment, the coating layer 206 and the furthercoating layer 207 have different spatial coverage (at a first lateralposition 276 the first coating layer 206 and the second coating layer207 overlap wherein at a second lateral position 278, the first coatinglayer 206 and the second coating layer 207 do not overlap). According toan embodiment, “overlap” in this sense means that the overlapping layersboth have dots in an overlap position. This is also illustrated in FIG.9, where each of the coating layer 206 and the further coating layer 207comprises a dot 264, 264-1 at the first lateral position.

The different spatial coverage results in a thickness variation 280 inthe layer package 274 wherein the layer package 274 has a first heighth3 (corresponding to a first thickness 282) at the first lateralposition 276 and has a second height h1 (corresponding to the secondthickness 252) at the second lateral position 278. Hence, the thicknessvariation 280 of the layer package 274 defines (or corresponds to) asurface structure according to embodiments of the herein disclosedsubject matter, i.e. a structure in a surface of the layer package.

According to an embodiment, the layer package 274 includes voids (e.g.in a third position 284, e.g. if the second coating layer and inparticular the dot 266 would not be present). In such a case, and inaccordance with an embodiment, the magnitude of the thickness variationcorresponds to the thickness of the entire layer package 274 (indicatedat 282 in FIG. 9). It is noted that in general and in accordance with anembodiment a single coating layer 206 is sufficient for generating athickness variation if the coating layer comprises voids.

Finally it is noted that, if the coating layer shall act as a protectionlayer, according to an embodiment any voids and gaps (like the gap 260)in the coating layer are filled with coating material (e.g. with thesame or a different coating material) or are removed by compaction orthermal treatment (e.g. initiation of viscous flow) in particular so asto provide a continuous coating layer of constant thickness on thesubstrate. Last gaps usually fill at least during curing, in particularif the coating layer 206 is in a liquid state or in a softened state(undercooled liquid state) above Tg.

FIG. 10 shows a further printing device 400 according to embodiments ofthe herein disclosed subject matter.

According to an embodiment, the printing device 400 is configured fordirect printing on a substrate 210. Similar to the printing device 301shown in FIG. 4, the printing device 400 comprises one or more printingunits, e.g. three printing units 224, 225, 226 as shown in FIG. 10. Theprinting units 224, 225, 226 may be configured similarly or identicallyto the printing units described with regard to FIG. 4 except that theprinting units are configured (e.g. positioned for a applying itscoating material to the substrate 210 (and in particular to a surface211 of the substrate 210) to thereby form the coating layer 206 directlyon the substrate 210. In this regard the surface 211 of the substrate210 forms a target surface according to the herein disclosed subjectmatter. Accordingly, corresponding elements are indicated with identicalreference numbers and that the description thereof is not repeated here.Further it is noted, that any process described with regard to FIG. 4may also be performed with regard to embodiments described with regardto FIG. 10, except that referring to the transfer element 204 referenceis made to the substrate 210 (due to the direct printing process) andinstead of referring to making contact of the coating layer and thesubstrate reference is made to the final curing. The same is applicablevice versa.

The printing device 400 further comprises a curing device 402 forfinally curing the coating layer 206 on the substrate 210. Further, theprinting device 400 comprises a transfer device 404 which is configuredfor transferring the substrate 210 to the printing units 224, 225, 226and subsequently (in a direction 410) to the curing device 402 and,optionally to further devices (e.g. 229, 232 described below) of theprinting device 400, if present. According to an embodiment, thetransfer device 404 comprises a conveyor belt 406 which extends abouttwo spaced apart pulleys 408.

Different from what is shown in FIG. 10 the curing device 402 can alsobe located in a separate location. Furthermore the substrate 210 couldalso be preheated due to the fact that it was pre-coated before with apowder coating and directly after curing the substrate is given to theprinting device 400. The same could also be the case when indirectprinting is done.

In a special embodiment a pre-coating (not shown in FIG. 10) was not—atleast fully cured—before the coating material 237 was applied on thesubstrate (in this case the pre-coating can be assumed to be thesubstrate). This pre-coat can be applied by NIP or by conventional meanslike powder coating or liquid coating. In the same or another embodimentthe coating layer was—at least fully cured—before a top coat (not shown)was applied on the coating layer. This top coat can be applied by NIP orby conventional means like powder coating or liquid coating.

According to an embodiment, the printing device 400 comprises an energytransfer device 229 for transferring energy 230, e.g. in the form ofinfrared radiation, into the coating layer 206 on the substrate 210.According to an embodiment, the energy 230 is provided at a ratesufficient to induce viscous flow in the coating layer 206 on thesubstrate 210. According to another embodiment, the energy 230 isprovided at the rate sufficient to partially cure the coating layer 206on the substrate 210.

According to a further embodiment, inducing viscous flow or partialcuring may be performed after application of each individual coatingmaterial. To this end, for example according to an embodiment and energytransfer device 229 may be provided after each printing unit 224, 225,226 (not shown).

Further, according to an embodiment, a compaction device 232 isprovided, wherein the compaction device is configured for compacting thecoating layer 206 on the substrate 210 before the final curing of thecoating layer 206. The operation of a roller 234 of the compactiondevice 232 in FIG. 10 is similar or identical to the operation describedwith regard to the compaction device 232 of FIG. 4. Accordingly, thesame reference numbers are used in the description thereof is notrepeated here.

According to an embodiment, after each printing unit (in conveyingdirection 410 of the transfer element/substrate) a compaction device maybe located for compacting a coating layer before a further coating layeris applied on the coating layer.

For controlling the entities and devices of the printing device 400, acontrol device 216 according to embodiments of the herein disclosedsubject matter is provided.

FIG. 11 shows a further printing device 500 according to embodiments ofthe herein disclosed subject matter.

Some entities (or features) of the printing device 500 which are similarto entities (or features) of the printing device 400 of FIG. 10 areindicated with the same reference signs and the description thereof isnot repeated here. Rather, some differences which are in accordance withembodiments of the herein disclosed subject matter are described withregard to FIG. 11.

The printing device 500 comprises one or more printing units 524, 525.The printing units 524, 525 do not include an intermediate transferelement as described with regard to FIG. 4. Rather, the printing units524, 525 only comprise an OPC 227. In accordance with an embodiment, theprinting units 524, 525 are configured for applying the coating materialfrom the OPC 227 directly to the target surface, e.g. directly to thesubstrate 210 (direct printing).

According to an embodiment, one or more coating layers, in particulartwo or more coating layers 206, 207 are applied to the target surface(e.g. of the substrate 210, as shown in FIG. 11) in order to provide athicker layer package 274 (and hence a larger thickness of the finalcoating). In particular, with two or more coating layers 206, 207 largerthickness variations of the layer package 274 are possible. According toan embodiment, for each coating layer a separate printing unit 524, 525is provided. If the two or more printing units 524, 525 receive the samecoating material 237, a single-color layer package with a thicknessaccording to embodiments may be obtained. It is noted that FIG. 11 showsthe printing device 500 at an instant in time where the coating 206 hasalready been entirely applied by a first printing unit 524 and whereinthe further coating layer 207 has been partly applied by the secondprinting unit 525.

In accordance with an embodiment, the printing device 500 may be astandalone printing device. According to an embodiment the substrate 210with the layer package 274 applied thereon is removable from theprinting device for storage or for transport to a curing device (notshown in FIG. 11).

According to an embodiment, the surface structure of the layer packageis provided by suitably controlling the at least one printing unit 524,525 of the printing device, to provide two or more coating layers 206,207 with different spatial coverage, as described with regard to FIG. 4.In accordance with a further embodiment, the roller 234 of thecompaction device 232 may have a structured surface to therefor embossthe desired surface structure into the layer package 274.

It is noted that in accordance with embodiments of the herein disclosedsubject matter, one or more entities (e.g. printing device, printingunits, energy transfer device, compaction device, etc.) disclosed withregard to the drawings may be considered as be belonging to a processingdevice as described herein.

FIG. 12 shows a part of a coating layer 206 according to embodiments ofthe herein disclosed subject matter.

In accordance with an embodiment, the coating material and hence thecoating layer 206 generated therefrom comprises a first material portion601 and a second material portion 602.

According to an embodiment, the first material portion 601 comprises orconsists of at least one effect particle 604, 605. In accordance with anembodiment, each effect particle 604, 605 comprises at least one (atleast partially covered) effect pigment 606, the effect pigment 606being at least partially covered by a curable polymeric matrix 608.According to an embodiment the curable polymer matrix 608 may beconfigured and/or treated (e.g. regarding composition, heat treatment,partial curing, etc.) according to embodiments being related to thefurther coating layer disclosed herein.

According to a further embodiment, the second material portion 602 is acoating material configured according to embodiments of the hereindisclosed subject matter which do not refer to the effect particles.

According to an embodiment, a first effect particle 604, which islocated in a vicinity of a surface 610 of the coating layer, is alsolocated in the vicinity of a second effect particle 605, thus providinga channel of low absorption of visible light from an effect pigment ofthe second particle 605 to the surface 610. In this regard the term “inthe vicinity of” includes “in contact with” or within a distance of lessthan 0.1 μm, e.g. less than 1 μm or in particular less than 10 μm.

According to an embodiment, the coating layer 206 is applied to asubstrate (not shown in FIG. 12) which comprises a base coat 612.Further, the coating layer 206 may be covered with a top coat 614according to embodiments of the herein disclosed subject matter.

EXAMPLES

In the following exemplary examples are described which furtherillustrate embodiments of the herein disclosed subject matter.

In the following, whenever digital powder is mentioned this refers tothe coating material (for Non-impact printing/NIP) according toembodiments of the herein disclosed subject matter. Parts of acomposition are parts by weight.

EXAMPLES

In order to produce the following toner examples, all components werepremixed in a high-speed mixer for 1 min, followed by extrusion in atwin-screw ZSK-18 extruder. The melted compound was cooled down,granulated and finely ground to produce a powder with the desired grainsize distribution. The preferred grinding and classification was done byjet-milling with a Multino M/S/N opposed jet mill from NOLL if notstated otherwise. Before printing silica (0.5% HDK H05 TD+1% HDK H30™from Wacker Silicones) was bonded to the powders using a Henschel MixerMB10.

Example 1—PES-PT910

The mixture was composed of 600 parts of Uralac® P3490 (DSM), asaturated carboxylated polyester resin, 45 parts of Araldite® PT-910(Huntsman), 8 parts of Accelerator DT-3126 (Huntsman), 7 parts ofBenzoin and 13 parts of charge control agent salicylic acid DL-N24(Hubei DingLong Chemical Co., Ltd). This composition gave a transparentformulation. For different colours (Cyan, Magenta, Yellow, Black andWhite) 33 parts of Heliogen Blue K7090 (BASF) for cyan, 33 parts ofCinquasia Violet L5120 (BASF) for magenta, 106 parts of Sicopal YellowL1100 (BASF) for yellow, 33 parts of Printex 90 BEADS (Orion EngineeredCarbons) for black or 200 parts of TI Select TS6200 (DuPont) for whitewere added. All components were premixed in a high-speed mixer for 1 minand then extruded in a twin-screw ZSK-18 extruder. The compound obtainedwas then cooled down, granulated, fine ground and classified to obtain apowder having a D50 of up to 12 μm if not otherwise described.

Hardening (curing the coating layer on the substrate) was done at atemperature of 200° C. for 10 minutes.

Example 2—PES-Primid (Super Durable)

The mixture was composed of 650 parts of Uralac P3230, a saturatedpolyester resin, 49 parts of Primid XL 552 (EMS Chemie), 7 parts ofBenzoin and 14 parts of charge control agent salicylic acid DL-N24(Hubei DingLong Chemical Co., Ltd). This composition gave a transparentformulation. For different colours (Cyan, Magenta, Yellow, Black andWhite) 32 parts of Heliogen Blue K7090 (BASF) for cyan, 32 parts ofCinquasia Violet L5120 (BASF) for magenta, 100 parts of Sicopal YellowL1100 (BASF) for yellow, 32 parts of Printex 90 BEADS (Orion EngineeredCarbons) for black or 190 parts of TI Select TS6200 (DuPont) for whitewere added. All components were premixed in a high-speed mixer for 1 minand then extruded in a twin-screw ZSK-18 extruder. The compound obtainedwas then cooled down, granulated, fine ground and classified to obtain apowder having a D50 up to 12 μm if not otherwise described.

Hardening was done at a temperature of 200° C. for 5 minutes.

Example 3—PUR

The mixture was composed of 500 parts Uralac® P 1580 (DSM), a saturatedOH-polyester resin, 215 parts of Vestagon® B 1530 (Evonik), and 14 partsof charge control agent salicylic acid DL-N24 (Hubei DingLong ChemicalCo., Ltd). This composition gave a transparent formulation. Fordifferent colours (Cyan, Magenta, Yellow, Black and White) 36 parts ofHeliogen Blue K7090 (BASF) for cyan, 36 parts of Cinquasia Violet L5120(BASF) for magenta, 114 parts of Sicopal Yellow L1100 (BASF) for yellow,36 parts of Printex 90 BEADS (Orion Engineered Carbons) for black or 215parts of TI Select TS6200 (DuPont) for white were added. All componentswere premixed in a high-speed mixer for 1 min and then extruded in atwin-screw ZSK-18 extruder. The compound obtained was then cooled down,granulated, fine ground and classified to obtain a powder having a D50up to 12 μm if not otherwise described.

Hardening was done at a temperature of 200° C. for 15 minutes.

Example 4—PES-TGIC

The mixture was composed of 790 parts Uralac® P 6401 (DSM), a saturatedcarboxylated polyester resin, 60 parts of TGIC (Huntsmann), 5 parts ofBenzoin and 17 parts of charge control agent salicylic acid DL-N24(Hubei DingLong Chemical Co., Ltd). This composition gave a transparentformulation. For different colours (Cyan, Magenta, Yellow, Black andWhite) 43 parts of Heliogen Blue K7090 (BASF) for cyan, 43 parts ofCinquasia Violet L5120 (BASF) for magenta, 137 parts of Sicopal YellowL1100 (BASF) for yellow, 43 parts of Printex 90 BEADS (Orion EngineeredCarbons) for black or 257 parts of TI Select TS6200 (DuPont) for whitewere added. All components were premixed in a high-speed mixer for 1 minand then extruded in a twin-screw ZSK-18 extruder. The compound obtainedwas then cooled down, granulated, fine ground and classified to obtain apowder having a D50 up to 12 μm if not otherwise described.

Hardening was done at a temperature of 200° C. for 10 minutes.

Example 5—PES-Epoxy

The mixture was composed of 350 parts of Uralac® P 3450 (DSM), asaturated carboxylated polyester resin, 150 parts of Araldite® GT 7004(Huntsmann), 4 parts of Benzoin and 10 parts of charge control agentsalicylic acid DL-N24 (Hubei DingLong Chemical Co., Ltd). Thiscomposition gave a transparent formulation. For different colours (Cyan,Magenta, Yellow, Black and White) 25 parts of Sunfast Blue 15:4(SunChemical) for cyan, 25 parts of Quindo Magenta (SunChemical) formagenta, 25 parts of Fanchon Yellow 180 (SunChemical) for yellow, 13parts of NiPex 60 (Orion Engineered Carbons) for black or 150 parts ofTI Select TS6200 (DuPont) for white were added. All components werepremixed in a high-speed mixer for 1 min and then extruded in atwin-screw ZSK-18 extruder. The compound obtained was then cooled down,granulated, fine ground and classified to obtain a powder having a D50up to 12 μm if not otherwise described.

Hardening was done at a temperature of 160° C. for 15 minutes.

Example 6—Unsaturated PES-UV System as Example for Potential UV CurableSystem which can be Incorporated into the Coatings According to theInvention

The mixture was composed of 350 parts of UVECOAT 2100 (Allnex), anunsaturated polyester resin, 13 parts of photo initiators, 2 parts ofBenzoin and 7 parts of charge control agent salicylic acid DL-N24 (HubeiDingLong Chemical Co., Ltd). This composition gave a transparentformulation. For different colours (Cyan, Magenta, Yellow, Black andWhite) 18 parts of Sunfast Blue 15:4 (SunChemical) for cyan, 18 parts ofQuindo Magenta (SunChemical) for magenta, 18 parts of Fanchon Yellow 180(SunChemical) for yellow, 9 parts of NiPex 60 (Orion Engineered Carbons)for black or 110 parts of TI Select TS6200 (DuPont) for white wereadded. All components were premixed in a high-speed mixer for 1 min andthen extruded in a twin-screw ZSK-18 extruder. The compound obtained wasthen cooled down, granulated, fine ground and classified to obtain apowder having a D50 up to 12 μm if not otherwise described.

Hardening was done at a temperature of 140° C. for 2 minutes under UVlight with a dose of 2.5 J/cm².

Example 7—PES-Epoxy

The mixture was composed of 440 parts of Crylcoat 1501-6 (Allnex), asaturated polyester resin, 290 parts of Araldite® GT7220 (Huntsman), 25parts of Reafree C4705-10 (Arkema), 10 parts of Eutomer B31 (EutecChemical), 2 parts of Tinuvin 144 (BASF) and 15 parts of charge controlagent salicylic acid DL-N24 (Hubei DingLong Chemical Co., Ltd). Thiscomposition gave a transparent formulation. For different colours (Cyan,Magenta, Yellow, Black and White) 38 parts of Sunfast Blue 15:4(SunChemical) for cyan, 38 parts of Quindo Magenta (SunChemical) formagenta, 38 parts of Fanchon Yellow 180 (SunChemical) for yellow, 19parts of NiPex 60 (Orion Engineered Carbons) for black or 230 parts ofTI Select TS6200 (DuPont) for white were added. All components werepremixed in a high-speed mixer for 1 min and then extruded in atwin-screw ZSK-18 extruder. The compound obtained was then cooled down,granulated, fine ground and classified to obtain a powder having a D50up to 12 μm if not otherwise described.

Hardening was done at a temperature of 135° C. for 5 minutes using aninfrared oven.

Example 8—PES-Primid (Durable)

The mixture was composed of 600 parts of Uralac P865, a saturatedpolyester resin, 32 parts of b-Hydroxyalkylamide (EMS Chemie), 6 partsof Benzoin and 12 parts of charge control agent salicylic acid DL-N24(Hubei DingLong Chemical Co., Ltd). This composition gave a transparentformulation. For different colours (Cyan, Magenta, Yellow, Black andWhite) 25 parts of Heliogen Blue K7090 (BASF) for cyan, 25 parts ofCinquasia Violet L5120 (BASF) for magenta, 80 parts of Sicopal YellowL1100 (BASF) for yellow, 25 parts of Printex 90 BEADS (Orion EngineeredCarbons) for black or 150 parts of TI Select TS6200 (DuPont) for whitewere added. All components were premixed in a high-speed mixer for 1 minand then extruded in a twin-screw ZSK-18 extruder. The compound obtainedwas then cooled down, granulated, fine ground and classified to obtain apowder having a D50 up to 12 μm if not otherwise described.

Hardening was done at a temperature of 170° C. for 15 minutes.

Example 9—Acrylics

The mixture was composed of 405 parts of Fine-Clad A-253 (Reichhold), aglycidyl acrylic resin, 95 parts of dodecanedioic acid (DuPont), 5 partsof Benzoin and 10 parts of charge control agent salicylic acid DL-N24(Hubei DingLong Chemical Co., Ltd). This composition gave a transparentformulation. For different colours (Cyan, Magenta, Yellow, Black andWhite) 25 parts of Heliogen Blue K7090 (BASF) for cyan, 25 parts ofCinquasia Violet L5120 (BASF) for magenta, 80 parts of Sicopal YellowL1100 (BASF) for yellow, 25 parts of Printex 90 BEADS (Orion EngineeredCarbons) for black or 150 parts of TI Select TS6200 (DuPont) for whitewere added. All components were premixed in a high-speed mixer for 1 minand then extruded in a twin-screw ZSK-18 extruder. The compound obtainedwas then cooled down, granulated, fine ground and classified to obtain apowder having a D50 up to 12 μm if not otherwise described.

Hardening was done at a temperature of 150° C. for 20 minutes.

Example 10—PES-Epoxy (Crystalline Resin Added)

The mixture was composed of 259 parts of Polyester 1, a saturatedcarboxylated polyester resin with an acid value between 68 and 76 mgKOH/g and a viscosity between 2.0 and 3.5 Pa*s, 226 parts of D.E.R. 642U(Dow Chemicals), an epoxy resin, 160 parts of Sirales PE 5900 (SIRIndustriale), a crystalline resin, 15 parts of Eutomer B31 (EutecChemical) and 13 parts of charge control agent salicylic acid DL-N24(Hubei DingLong Chemical Co., Ltd). This composition gave a transparentformulation. For different colours (Cyan, Magenta, Yellow, Black andWhite) 32 parts of Sunfast Blue 15:4 (SunChemical) for cyan, 32 parts ofQuindo Magenta (SunChemical) for magenta, 32 parts of Fanchon Yellow 180(SunChemical) for yellow, 16 parts of NiPex 60 (Orion EngineeredCarbons) for black or 190 parts of TI Select TS6200 (DuPont) for whitewere added. All components were premixed in a high-speed mixer for 1 minand then extruded in a twin-screw ZSK-18 extruder. The compound obtainedwas then cooled down, granulated, fine ground and classified to obtain apowder having a D50 up to 12 μm if not otherwise described.

Hardening (curing) was done at a temperature of 130° C. for 5 minutesusing an infrared oven.

1. Tropical Test

-   -   In this segment described is the procedure used to test the        adhesion of a coating or printing over different surfaces,        coated or not coated. The procedure follows the norm: EN ISO        6270-1 and EN ISO 6270-2.    -   Examples of different results:    -   Sample 1:

Example 7 Magenta after more than 1008 h at 40° C. and 100% humidity anddoing the Cross Cut test (EN ISO 2409) there is no delamination of theprinting from the base coat (Powder coating based on polyester incombination with b-Hydroxyalkylamide). It shows a really good adhesionto the substrate.

-   -   Sample 2:

Example 7 Magenta with a smaller PSD compared to Sample 1 (see table Ibelow) after more than 1008 h at 40° C. and 100% humidity and doing theCross Cut test (EN ISO 2409) there is no delamination of the printingfrom the base coat (Powder coating based on polyester in combinationwith b-Hydroxyalkylamide). It shows a really good adhesion to thesubstrate.

Sample 3:

Example 7 CMYK with a PSD described in the table with no pretreatmentfailed the test 336 h at 40° C. and 100% humidity doing the Cross Cuttest (EN ISO 2409). There is delamination of the printing from thesubstrate of the ceramic tile. It shows no good adhesion to thesubstrate.

The results are summarized in the table below:

TABLE I Summary of tropical test results TT 336 h (2nd TT 1008 h + 1 dayprinting week in) outside coating Adhesion Adhesion Sam- Sub- BaseDigital thickness cross- Visual cross- Visual ple strate Coat Powder PSD(μm) (μm) nail hatch control nail hatch control 1 Alu- Powder Example 7d10 = 7-8; 8-10 ok GT0 ok ok GT0 ok minium Coating Magenta d50 = 11-12;d90 = 15-16 2 Alu- Powder Example 7 d10 = 6-7; 8-10 ok GT0 ok ok GT0 okminium Coating Magenta d50 = 9-10; d90 = 13-14 3 Ceram- — Example d10 =8-9; 15-25 not GT5 ok — — — ic Tile 7 CMYK d50 = 12-13; passed d90 =19-20

2. Pretreatment of Substrates

In this segment described is that in general any substrate can beprinted if the temperature tolerance of the material can withstand thecuring process (hardening temperatures) needed by the digital powderused in that case. Another topic is the adhesion of each coating orprinting on the surface of the substrate. As a regular way to test thisadhesion the combination of a couple of tests is used:

TABLE II Test normatives used for testing pretreatment of substrates“Tropical-Test” EN ISO Paints and varnishes—Determination 6270-1 ofresistance to humidity—Part 1: Continuous condensation “Gitterschnitt”EN ISO Paints and varnishes—Cross-cut test 2409

Powder Coated Surfaces:

-   -   In general any powder coated substrate (substrate with base coat        made by conventional powder coating) can be printed with no        pretreatment. Just a simple cleaning with isopropanole to remove        the possible dirtiness left by handling the materials.    -   The better or worse adhesion of the printing over the coated        surface depends on how the chemistries of printing materials and        the powder coatings fit.    -   Sample 1: Printing of Example 7 CMYK over a Powder Coated medium        density fiberboard (MDF) with a white powder coating based on        the combination of a polyester with an epoxy resin. The base        coat was just cleaned and adhesion was good because the coating        material (printing) comprises the same resin system like the        pre-coating on the substrate.    -   Sample 2: Printing of Example 7 CMYK over a Powder Coated        Aluminium with a white powder coating based on polyester in        combination with b-Hydroxyalkylamide. The base coat was just        cleaned and adhesion was sufficient.

Not Powder Coated Surfaces

-   -   For substrates with no base coat made by conventional powder        coating a differentiation between metal, medium density        fiberboards (MDF), glass, ceramic and plastic substrates has to        be made. As a common step, all surfaces are first cleaned with a        gun with pressured air to remove rests of dust over the surface        and/or whipping with a textile material with isopropanol to        remove the possible dirtiness left by handling in the case of        metal, glass, ceramics and plastics.    -   Glass is subjected to a special pretreatment like with pyrosil        flame and an adhesion promoter. Metal does not need any        pretreatment, just the right temperature to fix the printing.        MDF needs to be printed with a certain temperature to fix the        printing but the temperature tolerance of the MDF must not be        crossed to keep its mechanical properties. The best option with        this materials is to use the infrared oven, this way only the        surface of the MDF is heated and the evaporation of water is        kept under control. Ceramic tiles can be printed with the help        of temperature but to achieve a good adhesion extra        pretreatments have to be done. Otherwise, the adhesion fails        after certain time.    -   Sample 3: Printing of Example 7 CMYK over not coated glass with        no pretreatment. Printing adheres to the surface but fails after        a certain time with tropical test.    -   Sample 4: Printing of Example 7 CMYK on a ceramic tile with no        pretreatment. Adhesion failed after 336 h with tropical test.

3. UV-Stability—Charge Control Agent

In this segment the procedures used to test the UV stability of tonermaterials are described. Modifications of Example 8 with differentcommercially available charge control agents (CCAs) with differentthicknesses and different pigments were tested (see Table). The QUVtests were performed according to the following tests:

TABLE III Test normatives for QUV tests “UV QUV Tests: remaining glossafter 300 hours of UV stability” exposure according to the GSBInternational AL 631 - Part VII Segment 20.1 Kurzbewitterung UV-B (313)is at least 50%. EN ISO 16474-2 Paints and varnishes - Methods ofexposure to laboratory light sources - Part 2: Xenon-arc lamps EN ISO16474-3 Paints and varnishes - Methods of exposure to laboratory lightsources - Part 3: Fluorescent UV lamps

TABLE IV results of QUV tests Sam- charge control ple Pigment chargeagent n° Colour control agent amount [%] Result 1 Magenta Copy Charge 2acceptable (grey) 2 T99 (black) 2 good 3 T77 (black) 2 bad 4 TRH-BD(black) 2 acceptable 5 DL-N24 (white) 2 good 6 — 0 good 1 Black T77(black) 2 bad 2 DL-N24 (white) 2 good 3 DL-N24 + Copy 1, 5 + 1, 5 goodCharge (grey) 4 — 0 good

The results show really good UV stability of the material without chargecontrol agent, with DL-N24 (Ding Long) white charge control agent andwith T99 black (Hodogaya). Also combinations of different charge controlagents were tested not improving the best results of no charge controlagent, DL-N24 and T-99.

-   -   Example 8: The results show really good UV stability of the        material without charge control agent (samples 6 magenta and 4        black in Table IV), with DL-N24 (Ding Long) white charge control        agent (samples 5 magenta and 2 black in Table IV) and with T99        black (Hodogaya) (samples 2 magenta in Table IV). The negative        effect of the UV light over the surface of the plates (mainly        the two belonging to T77 from Hodogaya) is a severe loss of        gloss (samples 3 magenta and 1 black in Table IV).

4. UV Protection

In this segment it is describe the surprising effect of retention ofgloss of a powder coated material Example 7 (this material cannotwithstand the QUV test) after 300 h of UV exposure in a QUV test, when atop coat of a transparent powder coating formulation based on polyesterin combination with b-Hydroxyalkylamide is applied. The top coat isapplied with different thicknesses and curing treatments.

Usually, the UV stability of Example 7 is very poor but it wassurprisingly found that a layer of UV stable powder coat on top helps towithstand the 300 h QUV test. The procedures for the QUV test are listedin table below:

TABLE V Test and normatives for UV stability “UV QUV Tests: remaininggloss after 300 hours of UV stability” exposure according to the GSBInternational AL 631 - Part VII Segment 20.1 Kurzbewitterung UV-B (313)is at least 50%. EN ISO Paints and varnishes - Methods of exposure16474-2 to laboratory light sources - Part 2: Xenon-arc lamps EN ISOPaints and varnishes - Methods of exposure to 16474-3 laboratory lightsources - Part 3: Fluorescent UV lamps

The materials were cured in a convection oven with the following curingconditions:

Example 7: T=160° C.; t=15 min

Example 8: T=200° C.; t=15 min

TABLE VI Coating parameters for testing UV stability Thickness CuringTop coat Curing top Sam- [μm] Example thickness [μm] coat ple Example 77 Example 8 Example 8 A 40 Yes — — B 40 Yes 40 Yes C 40 Yes 80 Yes D 40No 40 Yes E 40 No 80 Yes

Results:

TABLE VII results of testing UV stability Start gloss Reten- Sam-(measured Final tion ple at 60°) gloss [%] Comments A 0.8 0.4 50 Lowgloss and low retention as expected B 93.6 93.4 99.7 Good gloss,retention and surface C 87 95.1 106 Good gloss, retention and notperfect surface D 7.5 6.2 83 Really bad surface E 62.5 53.8 86 Reallybad surface

For a good surface the materials need separated curing like aprimer+curing followed to top coat+curing. With those tests thecombination of a transparent top coat of an UV stable formulation(polyester in combination with b-Hydroxyalkylamide) and a color basecoat of a usually non-UV stable formulation (Example 7) can withstandthe QUV test. This transparent film brings an UV protection for outdoorapplications.

Samples: Tests of a non-UV stable powder (Example 7) with (“sample B”:40 μm thickness; “sample C”: 80 μm thickness) and without anytransparent UV-stable top coat to compare (“Sample A”).

On Sample A, without top coat, failure was observed. An area where theUV light was hitting the coating is clearly visible with lower gloss andcolor.

With the other two (“sample B” and “Sample C”) that effect is not seenand furthermore the top coat increases the glossy effect of the originalmaterial.

5. Mechanical Tests

Surprisingly it was found that printed films of coatings of Examples 2,3 and 7 can withstand the mechanical tests (given in the Table of testnormatives) applied over different substrates with differentthicknesses. Choosing the right combinations of Digital Powder,substrate and Powder coating, this offers a great opportunity to usethose materials in any kind of Industrial Indoor and/or outdoorapplications as a printed finishing with high mechanical properties,comparable to the properties of the base coat made with coated PowderCoating.

In a first step, all new formulations are tested as powder coatingsfollowing the norms listed in the table of test normatives. The tableshows tests of Example 2 powder coated over aluminium plates.

TABLE VIII.a Results for mechanical tests, Outdoor Test results AdhesionScratch Example 2 DIGITAL Powder coated Mechanical testing Dornbiege-resistance Xenon samples over aluminium plates “Erichsen testGitterschnitt UV- test Curing tiefung” Kugelschlag (mandrel (crosscutstability (1000 h) Base Coated Thickness rates (Erichsen (ball bendingadhesion Retention Retention coat color (μm) (Convection) cupping)punch) test) test) [%] [%] no Transparent ca. 80 200° C. - 10′ OK SlightOK OK 94 98.4 base cracks/ coat ok no white 60-70 200° C. - 10′ OKSlight Cracks OK 89 101.4 base cracks/ coat ok no yellow ca. 72 200°C. - 10′ OK Slight Cracks OK 89 98.2 base cracks/ coat ok no magenta ca.60 200° C. - 10′ OK Slight Cracks OK 94 98.3 base cracks/ coat ok s nocyan 60-65 200° C. - 10′ OK Slight OK OK 93 102.9 base cracks/ coat okno black ca. 75 200° C. - 10′ OK Slight cracks OK 93 99.6 base cracks/coat ok

TABLE VIII.b Results for mechanical tests, Indoor Example 7 IndoorDIGITAL Powder, powder coated samples over Test results aluminium platesMechanical Scratch resistance Curing testing Adhesion Erichsen CoatedThickness rates Erichsen Cross cut 0.5 Erichsen Base coat color (μm)(Convection) Impact cupping 1 mm Newton 1 Newton Polyester - Transparent60 150° C. - 10′ slight OK GT 0 OK Borderline/OK Epoxy cracks HybridPolyester - white 60 150° C. - 10′ slight OK GT 0 OK Borderline/OK Epoxycracks Hybrid

TABLE VIII.c Particle size distribution for coating materials subjectedto mechanical and chemical tests PSD (μm) d(10) d(50) d(90) Example 213,149 32,829 59,259 transparent Example 2 13,077 32,107 56,986 whiteExample 2 12,874 31,318 56,425 yellow Example 2 12,723 31,826 57,612magenta Example 2 13,335 32,675 58,299 cyan Example 2 13,922 33,3959,472 black Example 7 9.93 25.68 48.64 transparent Example 7 12.2626.39 46.77 white

In a second step, formulations of Table VIII.a and bare printed overdifferent substrates and tested again with the same norms to see if thereduction of thickness affects the performance.

TABLE IX.a Results for mechanical tests, Outdoor Example 2 OutdoorDIGITAL Powder, Test results printed over powder coated Adhesion Scratchaluminium plates Dornbiege- resistance Xenon Powder Mechanical testingtest Gitterschnitt UV- test Coating Curing “Erichsentiefung” Kugelschlag(mandrel (crosscut stability (2000 h) Base Printing Thickness rates(Erichsen (ball bending adhesion Retention Retention coat color (μm)(Convection) cupping) punch) test) test) [%] [%] Polyester black 12-15200° C. - 10′ OK Slight OK OK — 91.7 Primid cracks/OK

TABLE IX.b Results for mechanical tests, Indoor Example 7 Indoor DIGITALPowder, printed over powder coated Test results aluminium platesAdhesion Powder Mechanical testing Cross Scratch resistance CoatingPrinting Thickness Curing rates Erichsen cut Erichsen Erichsen Base coatcolor (μm) (Convection) Impact cupping 1 mm 0.5 Newton 1 NewtonPolyester - cyan 5-8 150° C. - 10′ detaching 3.9 mm GT 0 Passedborderline Epoxy of Hybrid basecoat Polyester - magenta 5-8 150° C. -10′ detaching 4.0 mm GT 0 — — Epoxy of Hybrid basecoat Polyester -yellow 5-8 150° C. - 10′ detaching 3.9 mm GT 0 — — Epoxy of Hybridbasecoat Polyester - black 5-8 150° C. - 10′ detaching 4.0 mm GT 0passed borderline Epoxy of Hybrid basecoat Polyester - black/4 20-30150° C. - 10′ detaching 0.7 mm GT 0 passed borderline Epoxy layers ofHybrid basecoat Polyester - black/4 20-30 150° C. - 10′ detaching 0.7 mmGT 0 — — Epoxy layers of Hybrid basecoat Polyester cyan 5-8 150° C. -10′ slight 1.1 mm GT 0 borderline not Primid cracks passed Polyestermagenta 5-8 150° C. - 10′ slight 3.2 mm GT 0 — — Primid cracks Polyesteryellow 5-8 150° C. - 10′ slight 1.6 mm GT 0 — — Primid cracks Polyesterblack 5-8 150° C. - 10′ slight 1.9 mm GT 0 borderline not Primid crackspassed

TABLE IX.c Particle size distribution for coating materials subjected tomechanical and chemical tests PSD (μm) d(10) d(50) d(90) Example 7yellow 6.11 9.08 13.39 Example 7 magenta 5.93 8.87 13.18 Example 7 cyan6.3 9.04 12.92 Example 7 black 6.27 8.95 12.73 Example 2 black 8.0411.98 17.72

All results are comparable to the formulations tested as powdercoatings.

-   -   Table of test normatives for mechanical tests:

TABLE X Test normatives used for mechanical tests Tests Standard Name“Scratch DIN 68861-4 Furniture surfaces - Part 4 - Resistance” Behaviorat scratches 0, 5 or 1 Newton″ “Bleistifthärte” EN ISO Paints andvarnishes - Determination (pencil hardness) 15184 of film hardness bypencil test ASTM D Standard Test Method for Film 3363 Hardness by PencilTest “Erichsentiefung” EN ISO 1520 Paints and varnishes - Cupping test(Erichsen cupping) “Gitterschnitt” EN ISO 2409 Paints and varnishes -Cross-cut test (Cross-cut adhesion test) “Dornbiegetest” EN ISO 1519Paints and varnishes - Bend test (mandrel bending (cylindrical mandrel)test) “Kugelschlag” ASTM D Standard Test Method for Resistance (ballpunch) 2794 of Organic Coatings to the Effects of Rapid Deformation ENISO Paints and varnishes - Rapid-deformation 6272-1 (impact resistance)tests - Part 1: Falling- weight test, large-area indenter EN ISO Paintsand varnishes - Rapid-deformation 6272-2 (impact resistance) tests -Part 2: Falling- weight test, small-area indenter “UV stability” QUVTests: remaining gloss after 300 hours of UV exposure according to theGSB International AL 631 - Part VII Segment 20.1 Kurzbewitterung UV-B(313) is at least 50%. EN ISO Paints and varnishes - Methods of 16474-1exposure to laboratory light sources - Part 1: General guidance “Xenontest” EN ISO Paints and varnishes - Methods of 16474-2 exposure tolaboratory light sources - Part 2: Xenon-arc lamps EN ISO Paints andvarnishes - Methods of 16474-3 exposure to laboratory light sources -Part 3: Fluorescent UV lamps

6. Chemical Tests

Surprisingly, it was found that printed films of coatings of Examples 2,3 and 7 can withstand the chemical tests (as given in the Table XV ofchemical test normatives) applied over different substrates withdifferent thicknesses. Choosing the right combinations of DigitalPowder, substrate and Powder coating, this offers a great opportunity touse those materials in any kind of Industrial Indoor and/or outdoorapplication as a printed finishing with high chemical properties,comparable to the properties of the base coat made with coated PowderCoating.

In a first step, all new formulations are tested as powder coatingsfollowing the norms listed in the table of chemical test normatives. Thetable XI below, shows tests of Example 2 powder coated over aluminiumplates.

TABLE XI.a Results of chemical tests for substrates with Example 2Outdoor coating material Example 2 DIGITAL Powder, powder coated samplesover Test results aluminum plates Chemical testing Thickness Curingrates Schüco- Base coat Coated color (μm) (Convection) Isopropanole FuelCleaner no base transparent ca. 80 200° C. - 10′ OK OK OK coat no basewhite 60-70 200° C. - 10′ OK OK OK coat no base yellow ca. 72 200° C. -10′ OK OK OK coat no base magenta ca. 60 200° C. - 10′ OK* OK* OK* coatno base cyan 60-65 200° C. - 10′ OK* OK* OK* coat no base black ca. 75200° C. - 10′ OK* OK* OK* coat *can be scratched easily

TABLE XI.b Results of chemical tests for substrates with Example 7Indoor coating material Example 7 Serie DIGITAL Powder, Test resultspowder coated samples over Chemical testing aluminium plates 24 h CoatedThickness Curing rates 1 h 48% 1 h Liquid 24 h Base coat color (μm)(Convection) Ethanol Coffee paraffin Water No base transparent 60 150°C. - 10′ passed passed passed passed coat No base white 60 150° C. - 10′passed passed passed passed coat

TABLE XII Particle size distribution for coating materials subjected tochemical tests PSD (μm) d(10) d(50) d(90) Example 2 13,149 32,829 59,259transparent Example 2 13,077 32,107 56,986 white Example 2 12,874 31,31856,425 yellow Example 2 12,723 31,826 57,612 magenta Example 2 13,33532,675 58,299 cyan Example 2 13,922 33,39 59,472 black Example 7 9.9325.68 48.64 transparent Example 7 12.26 26.39 46.77 white

In a second step, all formulations are printed over different substratesand tested again with same normatives to see if the reduction ofthickness affects the performance. The table XIII shows tests of Example7 printed over powder coated aluminium.

TABLE XIII.a Results for chemical tests for substrates with Example 7Indoor coating material Example 7 DIGITAL Powder, Test results printedsamples over Powder Chemical testing coated aluminium plates 24 hPrinting Thickness Curing rates 1 h 48% 1 h Liquid 24 h Base coat color[μm] (Convection) Ethanole Coffee paraffin Water Polyester in cyan 5-8150° C. - 10′ passed passed passed passed combination with Epoxy whiteSee above magenta 5-8 150° C. - 10′ passed passed passed passed Seeabove yellow 5-8 150° C. - 10′ passed passed passed passed See aboveblack 5-8 150° C. - 10′ passed passed passed passed See above black/420-30 150° C. - 10′ passed passed passed passed layers See above black/420-30 150° C. - 10′ passed passed passed passed layers Polyester + b-cyan 5-8 150° C. - 10′ passed passed passed passed Hydroxyalkylamidewhite See above magenta 5-8 150° C. - 10′ passed passed passed passedSee above yellow 5-8 150° C. - 10′ passed passed passed passed See aboveblack 5-8 150° C. - 10′ passed passed passed passed

TABLE XIII.b Results for chemical tests for substrates with Example 2Outdoor coating material Example 2 DIGITAL Powder, DIGITAL Powder,printed samples over Powder coated aluminium plates Test results PowderChemical testing Coating Base Printing Thickness Curing rates Schüco-coat color (μm) (Convection) Isopropanole Fuel Cleaner Polyester black12-15 200° C. - 10′ OK OK OK Primid

TABLE XIV Particle size distribution for coating materials subjected tochemical tests PSD (μm) d(10) d(50) d(90) Example 7 yellow 6.11 9.0813.39 Example 7 magenta 5.93 8.87 13.18 Example 7 cyan 6.3 9.04 12.92Example 7 black 6.27 8.95 12.73 Example 2 black 8.04 11.98 17.72

Table of Chemical Test Normatives:

TABLE XV Test normatives for chemical testing Test Standard NameChemical EN 12720 Furniture - Assessment of stability surface resistanceto cold “Chemikalien- liquids beständigkeit” EN ISO Paints andvarnishes - 2812-1 Determination of resistance to liquids - Part 1:Immersion in liquids other than water EN ISO Paints and varnishes -2812-2 Determination of resistance to liquids - Part 2: Water immersionmethod EN ISO Paints and varnishes - 2812-3 Determination of resistanceto liquids - Part 3: Method using an absorbent medium EN ISO Paints andvarnishes - 2812-4 Determination of resistance to liquids - Part 4:Spotting methods EN ISO Paints and varnishes - 2812-5 Determination ofresistance to liquids - Part 5: Temperature- gradient oven method

7. Film Hardness by Pencil Test

In this segment testing the film hardness via “pencil test” isdescribed. A standard pencil was used for testing according to the normgiven in the table. Examples 2 and 8 were tested and they were able toreach rating HB.

Table of Test Pencil Test Normatives:

TABLE XVI Test normatives for pencil test “Bleistifthärte” EN ISO 15184Paints and varnishes - (Pencil hardness) Determination of film hardnessby pencil test ASTM D 3363 Standard Test Method for Film Hardness byPencil Test

8. Chemical Stability IPA-MEK

In this segment tests are described using the basis of testing method EN12720 but with different liquids and time. 30 seconds MEK (methyl ethylketone) and IPA (isopropanol). The base for the testing method is givenin EN 12720.

High chemical resistant materials like Example 3 can even withstand theMEK test which is really one of the most critical chemical stabilitytests to a coating. All tested formulations according to the presentinvention were able to fulfill the IPA test.

It is observed that the MEK test fails with Example 7. Example 2 alsofails MEK test but with better performance than the previous material.Example 3 fullfils the MEK test with just 5 μm thickness.

9. Microscope Observations—PSD

In this segment described are the different results obtained withprintings regarding PSD (Particle Size Distribution) presenting someresults obtained from pictures done with a Digital Microscope Camera,dnt DigiMicro 2.0 Scale.

The different PSDs come together with the mill and classification usedfor grinding in each case. A summary is presented in the table togetherwith different PSD measurements.

TABLE XVII Tested particle size distributions (PSDs) Tested PSDs: NamePSD Mill H0: d10 = 6-8; d50 = 14-16; NEA Group Neumann & d90 = 24-26Esser GmbH. Typ ICM 2.4 H6600: d10 = 8-9; d50 = 12-13; Multino M/S/Nopposed jet d90 = 19-20 mill from NOLL H7500: d10 = 7-8; d50 = 11-12;Multino M/S/N opposed d90 = 15-16 jet mill from NOLL H9000: d10 = 6-7;d50 = 9-10; Multino M/S/N opposed d90 = 13-14 jet mill from NOLL

As found herein the PSD is really important to achieve good printingresults. Regularly, the smaller the diameter of the particles and thenarrower the PSD, the more homogeneous is the sample of powder and theeasier it is to control regarding powder charging and powder flowing.That leads to a better quality of the printing and a lower need of filmthickness.

It is observed that the resolution and the quality are improving fromH-0 to H-9000 because PSD is getting narrower and the diameter isgetting smaller.

The limit of lowest diameter used with traditional mechanically producedtoner is typically the limit of breathability of the particles. It isbelow 5 μm, where particles could be breathed directly into the lungs.

Nevertheless, one of the advantageous possibilities offered by theherein disclosed subject matter is the haptic-2,5D (relief) effect. Inorder to increase this effect, it is better to not reduce too much theparticle size diameter to still keep good resolution and qualitytogether with a better haptic effect. This was for example observed withpictures printed with a PSD HO. Hence, larger PSDs may be advantageousfor a relief effect.

10. No Additives—Flow Leveling

In this segment described is the surprising benefit of not using flowand/or levelling additives usually used in Powder coating technology toproduce Digital Powder formulations. An advantage comes with the specialway to apply the coating to any surface, “printing it by dots”. Thisprinting by dots includes the more homogeneous PSD and the smallerdiameter of the powder particles and also the more rounded shape of thepowder particles. Without being bound to theory it is thought that thesefactors (homogeneous PSD, small diameter of the powder particles andmore rounded shape of the powder particles (large sphericity)) help toget a more compacted film of the particles printed on a surface.

This way of application of the material, printing, makes possible, moreimportant, the desired resolution of the images printed on the substratebefore and after curing. Then, to try to keep the position of theprinted particles and to avoid as much as possible any possible bleedingeffect during curing could be mandatory. This fact and maybe togetherwith a lower thickness of the film with a single printing run applied byprinting, comparing with the thickness applied for Powder coatingtechnology by spraying (around 60 μm to 80 μm to keep mechanical,chemical and corrosion protection) makes it possible to avoid thoseadditives from the formulation and seems to be even preferred to be leftout to keep high resolution.

This situation with relatively low thickness (compared to powdercoatings) and application of dots offers also the possibility to removeany degassing agent from Digital Powder formulation of almost all resinsystems. One special remark needs to be done with primid systems. Here,the formation of water during curing demands the use of a certainquantity of degassing agents in most cases tested.

Some images of examples have been taken with a Digital MicroscopeCamera, dnt DigiMicro 2.0 Scale.

PSD H-0 with additives over transfer foil: still not transferred andalready cured. In the results, clearly visible bleeding effect has beenobserved.

PSD H-0 with additives transferred and cured. In the results, clearlyvisible bleeding effect has been observed as well.

PSD H-7500: no additives printed and cured. In the results, no bleedingeffect has been observed.

11. No Filler

In this segment described is the benefit of not using fillers usuallyused in Powder coating technology to produce digital powder formulations(i.e. a coating material according to embodiments of the hereindisclosed subject matter). Without being bound to theory it is thoughtthat the printing results are better because of the higher homogeneityof the powder particles, therefore charging and flowing of solidparticles is kept in a very good level.

12. Suitable Reactivity

Three different samples with different reactivities were prepared basedon the formulation of example 7 to show the influence of reactivity onthe final image as well as its preparation (Examples 7A, B and C). Thelow reactivity sample (Example 7C) was prepared without accelerator.

Formulations: Examples 7A to C: Here only the black formulations areshown.

TABLE XVIII Coating material tested for suitable reactivity Optimum Veryhigh Low reactivity reactivity reactivity Example Example ExampleRessources 7A % 7B % 7C % Crylcoat 1501-6 56.36 54.87 56.35 Araldite ®GT7220 38.19 38.13 39.16 Eutomer B31 (Accelerator) 0.95 2.5 chargecontrol agent 2 2 2 NiPex 60 (Carbon Black) 2.5 2.5 2.5 ResultsViscosity minimum/Pa s 6156 50260 257.3 Pill-flow -Tests/mm 30 14 106

Results—Viscosity

The viscosity was determined using a Rheometer, like the “AR 2000ex”, TAInstruments Ltd., measured at a defined heating rate. Dynamic modulus G′and loss modulus G″ are measured and the viscosity η* is calculated fromthese two operators. The minimum viscosity measurements were performedfor all of the samples (heating rate 5° C./min and when they arecompared following results can be concluded. Additionally, the pill flowlength was determined as described. This test provides results for theinteraction of viscosity and reactivity of the powders and is thereforea good tool to describe the effects of resolution and image quality. Ifthe reactivity is too high (high amount of accelerator) alreadypre-reaction occurs and the viscosity is really high already from thebeginning. The final coating obtained from such a coating material hasgood resolution but protective coating requirements such as chemicalresistance cannot be fulfilled sufficient for some industrialapplication. If reactivity is at the lower end of the limits describedaccording to the invention the flow is high which gives a worseresolution and additionally other artefacts occur.

It was found that Example 7A exhibits a good viscosity and therequirements on the final image can be fulfilled. In summary, example 7Bshows a too high reactivity and example 7C a viscosity at the lowerlimit which is not preferred especially for a coating system based epoxyand polyester resins.

13. Sphericity

In this segment described are the different results obtained withprintings regarding sphericity.

Not using any additional special treatment, heat and/or mechanical toround particles, the different sphericity comes from the grinding,depending on the mill (jet mills up to 0.93, Hammer mills below of thisrange). Regarding sphericity, an ideal perfectly rounded particle has avalue of 1.

In this situation, depending on which kind of Jet mill, thecircularity/sphericity can go from 0.93 to 0.97 based on the informationfound from different mill suppliers.

The sphericity/circularity, can be measured with different commerciallyavailable equipments like for example the Malvern FPIA 3000.

An important point here is it was found that the circularity/sphericityof the particles is linked with the resolution and quality. It was foundthat with less spherical/circular particles in certain examples morepronounced haptic effects of the final cured printing could be found.

14. Chargeability Tables+Silica

In this segment described are the different results obtained testingDigital Powders with a q/m meter from Epping GmbH. This machine providesresults comparing μC/gr vs time of activation using a soft blow withdifferent quantities of toner into a mixing of toner+carrier.

The Charging test is runned as follows:

-   -   a. Q/M-Meter, Soft blow off with 20 μm-Sieve; 10 to 300 min of        activation using a rolling machine.    -   b. Carrier reference is a commercially available Ferrite core        carrier CBO3 from Büro Compunication Wagner GmbH (Reference)    -   c. 25 g of mixing of Carrier+digital powder (8% to 10% digital        powder and hence 92% to 90% carrier, e.g. 8% or 10% of digital        powder).

In general, toner (powder) flowing (cohesiveness) and charging can bedifferent depending on particle size, PSD, charge control agent (typeand quantity) and external additives (type and quantity).

A suitable way to work in development is to fix (select) all corematerials first and then, in a second step, to test variousconcentrations of materials and kinds of external additives.

Of course working with different Series of materials, with differentresin systems the combination of all those factors will be different ineach case. But, at least as a starting point one standard process can beused.

Silica Bonding:

Silica bonding can be done with different kind of surface additives,individually or in combination of one or more. Like for example silicas.

Depending on the machine used, the settings of the mixing may differ,keeping always the temperature into the mixer controlled to avoidpre-reaction of the Powdery coating material. In this situation thematerials, procedure and machine used are described below.

Machine: Henschel Mixer MB10

Materials: Silica, quantity referred to the total weight of DigitalPowder, mixed with a combination of commercially available Silicas toimprove powder charging and powder flow (cohesiveness) like for example,0.5% HDK H05 TD (Silica A)+1% HDK H30™ (Silica B) from Wacker Silicones.

Procedure: bonding each silica in a three steps process. Each stepincludes bonding 10 seconds at 3700 rpm and a pause of 5 seconds inbetween the steps.

TABLE XIX Coating material for testing silica bonding Speed timeMATERIAL (rpm) (sek) intervalls Digital Powder + Silica A ~3700 10 3Digital Powder + Silica A + Silica B ~3700 10 3 T < 40° C.

The effect of adding silicas (referred to as “bonded” in FIG. 13) incombination with different PSDs was determined for example 7 magenta(different PSD)+silica bonding effect, used was a carrier with 8%digital powder. The results are shown in FIG. 13. The PSDs referred toin FIG. 13 are defined in table XVII above.

H8500 was in between H7500 and H9000 according to the PSD.

As a result, by reducing the PSD and using Silica bonding the chargingimproves.

Effect of Charge Control Agent in Combination with Silica:

Surprisingly, to add charge control agent into the formula did inparticular not bring a strong effect of charging improvement, butsurprisingly the color density of digital powders with a quantity lowerthan 2% of charge control agent drops dramatically down.

Using 2% charge control agent high color density has been observed. With1% charge control agent only low color density has been observed.

Effect of different carriers: different kind of commercially availableferrite core carriers with different diameters and coating compositionhave been tested with different examples, colors and quantities ofcarrier-toner mixing.

An important result was that the good combination ofFormulation-Silica-charge control agent and carrier, makes possible tohave a very stable charging not only with short times of activation,also with a long term activation. Those good combinations have to betested in each case.

15. Transfer

In this segment we describe the different results obtained testingDigital Powders with different transfer foils and different T(temperatures) and t (time). In order to get the best fixing of thepowder over the transfer foil/paper during printing, there was performeda fast treatment around 1-2 seconds at a T above the curing temperatureof each Digital Powder but with a low degree of curing avoiding theprinted dot crosslinking with transfer foil surface. The curingtemperature here is defined as the starting point of curing measured viadifferential scanning calorimetry at a heating rate of 20 K/min.

The materials used to run those tests are listed below:

Digital Powder: Example 7 magenta, Example 3 black

Final substrate: Aluminium powder coated with Polyester primed powdercoating white.

TABLE XX Transfer foil materials for testing effect of transfer foilThickness DSC- Format Foil Producer (μm) Material Surface MeasurementDIN A4 Hostaphan Mitsubishi 50 PET biaxial Matt Melting MT 50 Polyesterstretched point ~256° c. DIN A4 Hostaphan Mitsubishi 75 PET biaxial HighMelting RNK 75 Polyester stretched transparent point ~256° c. DIN A4Hostaphan Mitsubishi 75 PET biaxial Supermatt Melting STK 75 Polyesterstretched point ~256° c. DIN A4 Hostaphan Mitsubishi 50 PET biaxialsupermatt Melting STK 50 Polyester stretched point ~256° c.

The Transferring Step:

Above Tg but below melting point (where applicable with(semi)crystalline resins), where the material can be in its supercooledliquid state the combination of temperature T, time t and pressure P(T-t-P) makes a really big difference regarding resolution. The durationof the treatment is crucial. Too long treatments allows the powder toflow/bleed, losing the sharpness of the images.

A series of tests with different settings regarding T—t and keeping Pconstant were run.

First Test done with material Example 7 magenta at 150° C. for 1 minwith RNK 75 foil (in this case a highly reactive coating was used werethe curing normally already starts at least at 120 to 130° C.)→systemshowed too much pre-reaction. As a result the powder melted andcrosslinked onto the plate creating a bleeding effect because of the P.The crosslinking with a small quantity of material occurred on the foil,creating a really strong adhesion of the powder to foil's surface.

Second Test done with material Example 3 Black (Polyurethane based) at120° C. for 30 seconds with RNK 75→system showed bad delamination fromthe foil and high loss of resolution due the increased flow at this hightemperature. In this case no pre-reaction happened as here the reactionstarts at about 170° C. according to the DSC measurement shown in FIG.14.

(Further info obtained with this DSC measurement: An onset of glasstransition is observed at 51.1° C. (inflection point at 56.4° C.; endpoint at 61.1° C.; Delta-Cp 0.443245 mVs/(gk); mean: 56.8° C.). Furtheronset of glass transition is observed at 129.4° C. (inflection point at139.1° C.; End point at 144.6° C.; Delta-Cp 0.120134 mVs/(gk); mean:138.8° C.). Exothermal peaks are observed at 204.6° C. and 297.5° C. Anendothermal peak is observed at 281.5° C.).

Third test done with material Example 7 magenta at 150° C. for 3 minwith different kind of foils (STK 50, RNK 75 and MT 50) (in this case ahigh reactive coating was used were the curing normally already startsat least at 120 to 130° C.)→system showed a too high degree of curingand started the printed dot crosslinking with the transfer foil surface,consequently the transfer of material to the substrate was not possible.This effect was stronger with STK 50 foil, where plenty of materialremained on the foil after release. Instead, RNK 75 and MT 50 kept muchless powder on their surfaces after release. In all three cases, powderwas bleeding on the surfaces of the plates after transferring.

Fourth Test done with material Example 7 magenta at 80° C. for 1 minwith RNK 75 foil (in this case a high reactive coating was used were thecuring normally already starts at least at 120 to 130° C.)→here in thesupercooled state the transfer was much better and the printing qualityis kept in higher degree. The sample spots from low to high gradient ofcolor showed a corresponding continuous increasing of printed layerthickness, which showed surprisingly that the transfer quality wasimproved with higher material thickness. This example showed a bettercombination of T-t-P. Here material flow or bleed was kept and the finalsharpness of the image was higher.

Summarizing:

The pringing quality can be improved by selecting the correct transferfoil/paper.

Best results are obtained with the transfer to the substrate occuring inthe supercooled state (commented in Fourth test) and aligned combinationof heating rate and curing to prevent the flowing and/or bleeding of theprinted dots.

In order to help to achieve the best dot printing fixation over thetransfer foil and post transference of those dots from the transfer tothe final surface and keep the previous commented alignment, a fastpre-curing can additionally be used which prevents the flow of the printduring and before the curing happens. This can be achieved by adjustingthe quantity of a high reactivity catalyst and/or crosslinker so as toallow the partial-curing to take place already at low temperatures butis not in a suitable amount to make a full curing; and a not so reactivecuring catalyst/crosslinker for the final full curing. In other words,according to a special embodiment, the curing agent of the coatingmaterial comprises a first curing agent and a second curing agent,wherein at a certain (predetermined) temperature the reactivity providedby the first curing agent is higher than the reactivity provided by thecuring agent. According to a further embodiment an amount of the firstcuring agent is different (e.g. lower), e.g. by a factor x, than anamount of the second curing agent. According to an embodiment, thefactor x is chosen such that the precuring initiated by the first curingagent at the certain temperature and within a desired time window iseffected to the desired amount. So for example one option could be toimplement a certain concentration of unblocked Isocyanate crosslinkerswhich are known to react very fast but only in a concentration whichleads only to a partial curing which prevents further flow. Anotheroption would be to implement UV curing into each formulation of DigitalPowder and adjust the light energy, the UV initiator concentration andor the time in a way which prevents full curing. Then the UV reaction isfast enough to stop flow of the material and allows high resolutiontransfer which is furthermore more stable against environmental effectswhich can harm the resolution before the final curing on the substrate.

Final Remarks

It is noted, that depending on the composition of the coating material,the coating material may have more than one melt temperature, e.g. ifdifferent components or phases of the coating material have differentmelt temperatures. In such a case, the “melt temperature” referred to inembodiments of the herein disclosed subject matter is the lowest melttemperature out of the two or more different melt temperatures.

Likewise, depending on the composition of the coating material, thecoating material may have more than one curing temperature, e.g. ifdifferent components or phases of the coating material cure at differenttemperatures. In such a case, the “curing temperature” referred to inembodiments of the disclosed subject matter is the lowest curingtemperature out of the two or more different curing temperatures of athermal curing system.

Likewise, depending on the composition of the coating material, thecoating material may have more than one glass transition temperature,e.g. if different components or phases of the coating material undergothe glass transition at different temperatures. In such a case, the“glass transition temperature” referred to in embodiments of the hereindisclosed subject matter is the lowest glass transition temperature outof the two or more different glass transition temperatures.

It should be noted that any entity disclosed herein (e.g. components,elements and devices) are not limited to a dedicated entity as describedin some embodiments. Rather, the herein disclosed subject matter may beimplemented in various ways and with various granularity on device levelor software module level while still providing the specifiedfunctionality. Further, it should be noted that according to embodimentsa separate entity (e.g. a software module, a hardware module or a hybridmodule (combined software/hardware module)) may be provided for each ofthe functions disclosed herein. According to other embodiments, anentity (e.g. a software module, a hardware module or a hybrid module) isconfigured for providing two or more functions as disclosed herein.According to still other embodiments, two or more entities areconfigured for providing together a function as disclosed herein. It isnoted that a control device may be a distributed control device havingseveral parts. According to an embodiment, an exchange of informationbetween parts of the distributed control device may be performed bycommunicative coupling of the parts (e.g. by a computer network) or byproviding the substrate (or, in another embodiment, the transfer elementin case a transfer element is used) with the information in a form thatis readable by the receiving entity (e.g. coating layer applicationdevice, curing device). Such information to be exchanged may be forexample a curing program. A curing program may be specified by theprinting device depending on the printing parameters (e.g. theparticular coating material, treatment of the coating layer (partialcuring, viscous flow, etc.).

Further, it should be noted that while the exemplary coating layerapplication device and printing device in the drawings comprise aparticular combination of several embodiments of the herein disclosedsubject matter, any other combination of embodiment is also possible andis considered to be disclosed with this application and hence the scopeof the herein disclosed subject matter extends to all alternativecombinations of two or more of the individual features mentioned orevident from the text. All of these different combinations constitutevarious alternative examples of the invention.

Whenever herein it is referred to an entity for which differentembodiments are disclosed (e.g. a coating material, a coating layer, alayer package, a resin, a charge control agent, a curing agent, aprinting device, a coating layer application device, a transfer element,a substrate, a coating, a parameter range, etc.), it should beunderstood that this entity may be configured according to any one ormore the embodiments disclosed for this entity.

According to an embodiment, the coating layer (according to one or moreembodiments defined herein) is a coating layer that has been processedby a NIP device if not otherwise stated.

According to an embodiment, the coating material comprises one or morecolor pigments, in particular one or more of the following colorpigments:

Cyan: Sunfast Blue 15:4/Sun Chemical (C.I.: blue 15:4,Cu-phtalocyanine); Heliogen Blue D7110F/Ciba Specialty Chemicals (C.I.blue 15:4, Cu-phtalocyanine); Heliogen Blue K7090/BASF (C.I. blue 15:3,Cu-phtalocyanine); Sunfast Blue 15:3/Sun Chemical (C.I. blue 15:3,Cu-phtalocyanine.

Magenta: Quindo Magenta 2282120/Sun Chemicals (C.I. number 73907/73900,quinacridone); Cinquasia RED L4105HD/Ciba Specialty Chemicals (C.I.Violet 19, quinacridone); Cinquasia Viloet L5120/BASF (C.I. Violet 19,quinacridone); Hostaperm rosa E/Clariant (C.I. PR 122, quinacridone);Hostaperm RED E3B/Clariant (C.I. Violet 19, quinacridone); Hostaperm REDE5B02/Clariant (C.I. Violet 19, quinacridone).

Yellow: Fanchon yellow 180/Sun Chemicals (C.I.: PY180, Benzimidazolone);Fanchon yellow 151/Sun Chemicals (C.I.: PY151, Benzimidazolone); DuropalYellow 6218/Habich HMH (C.I.: PY184, Bismuth vanadate); Sicopal YellowL1100/BASF (C.I.: PY184, Bismuth vanadate)

Black: Nipex 60/Orion (carbon black); Printex 90 Beads/Orion (carbonblack); Spezial Schwarz/Evonik (carbon black)

White: TiSelect TS6200/DuPont (titanium dioxide)

In accordance with an embodiment, the coating material comprises one ormore effect pigments, in particular one or more of the following effectpigments: Iriodin 9612 Silver Grey Fine/EMD; PCU 1000 aluminiumpowder/Eckart Effect Pigments

According to an embodiment, the coating material comprises one or morelight and heat stabilizer, in particular one or more of the following:

UVA—UV absorbers: Tinuvin 479 (HPT—hydroxiphenyl-triazines); Tinuvin 405(HPT); Tinuvin 460 (HPT); K-Sorb 1577 (HPT); Tinuvin 928(BTZ—benzotriazole).

HALS—hindered amine light stabilizers: Tinuvin 152 (N-OR HALS); Tinuvin144 (N-alkyl HALS); Tinuvin 622 SF (oligomeric N-alkyl HALS); Chimassorb944 LD (oligomeric N-H HALS); Tinuvin 111 FDL blends (N-alkyl/N-alkylHALS); K-Sorb 111.

AO—Antioxidant: Irganox 1010 (hindered phenol, primary AO); Irganox 1076(hindered phenol, primary AO): Irganox 245 (hindered phenol, primaryAO); Irgafos 126 (phosphite, secondary AO); Irgafos 168 (phosphite,secondary AO); K.nox 126 (phosphite, secondary AO); K.nox 3114(phenolic, primary AO); Knox 1010 (phenolic, primary AO); K.nox 445(aminic AO).

It should be noted that the term “comprising” does not exclude otherelements or steps and the “a” or “an” does not exclude a plurality. Alsoelements described in association with different embodiments may becombined. It should also be noted that reference signs in the claimsshould not be construed as limiting the scope of the claims.

In order to recapitulate some of the above described embodiments of thepresent invention one can state:

Described is a coating material 237, 248, 268 being processable by NIPto form at least a part of a coating layer 206 representing an image.The coating material 237, 248, 268 comprises an amorphous component andis curable, e.g. thermally curable. Further, the coating material 237,248, 268 is configured for being applied with a thickness of at least 15μm.

Further described is a coating material in particular configured forgenerating a coating layer by non-impact printing, the coating materialbeing provided in the form of a plurality of particles and comprising: aresin, the resin comprising a curable resin component, the resin furthercomprising an amorphous resin portion, in particular wherein the resincomponent is at least partially thermally curable, in particular curableby a crosslinking agent able to react with functional groups of theresin component; and the coating material comprising a charge controlagent; wherein the content of charge control agent is at least 2 weightpercent based on the overall weight of coating material; and the coatingmaterial has a particle size distribution with a d10 value equal to orlarger than 5 μm, in particular with the d10 value being in a rangebetween 5 μm and 7 μm.

Further described is a coating material, in particular for generating acoating layer by non-impact printing, the coating material beingprovided in the form of particles and comprising: a curable resinpreferably an at least partially thermal curable resin and even more inparticular curable by a crosslinking agent able to react with functionalgroups of the resin, the resin comprising in particular an amorphousresin portion; wherein an average diameter of the particles is in arange between 1 μm and 25 μm; and wherein the particles have an averagesphericity larger than 0.7, in particular larger than 0.8, in particulara sphericity larger than 0.9.

Further described is a developer comprising: a carrier (e.g. at leastone carrier); and, in an amount of 10 wt-% or less, a coating material,in particular for generating a coating layer by non-impact printing, thecoating material being provided in the form of particles and comprising:a curable resin preferably an at least partially thermal curable resinand even more in particular curable by a crosslinking agent able toreact with functional groups of the resin, the resin comprising inparticular an amorphous resin portion; wherein an average diameter ofthe particles is in a range between 1 μm and 25 μm; and wherein theparticles have an average sphericity larger than 0.7, in particularlarger than 0.8, in particular a sphericity larger than 0.9; wherein, ifthe coating material is heated from room temperature with a heating rateof 5 K per minute, the coating material upon heating reduces itsviscosity down to a minimum viscosity and increases its viscosity uponfurther increase of the temperature;

wherein the minimum viscosity is in a range between 3 Pascal seconds and20000 Pascal seconds.

Further described is a coating material configured for generating acoating layer (206) by non-impact printing, the coating materialcomprising: at least one effect particle, comprising at least one atleast partially covered effect pigment, the effect pigment beingcovered, at least partially, by a thermally and/or radiation curablepolymeric matrix, wherein the polymer matrix is preferably transparent.

Further described is a non-impact printing device comprising: a coatingmaterial being curable and comprising a resin; the coating materialcomprising an amorphous resin portion in an amount of at least 30 w-%based on the overall amount of resin and comprising with respect to theentire amount of coating material less than 0.5 w-% of flow additive; aprinting unit, in particular an electrophotographic printing unit, beingconfigured for printing the coating material so as to form a coatinglayer, wherein the coating layer forms at least part of a layer packagecomprising at least one layer; the non-impact printing device beingconfigured for providing the layer package so as to define a surfacestructure with the layer package; wherein the surface structure isdefined by a thickness variation of the layer package; wherein thethickness variation is in a range between 1 μm and 1000 μm, inparticular in a range between 1 and 300 μm, and is in particular morethan 1 μm, in particular more than 5 μm, in particular more than 10 μmand in particular more than 20 μm.

Further described is a coating layer application device for applying acoating layer, which is located on a transfer element, to a substrate,the coating layer being formed from a coating material, in particular athermosetting coating material, the coating layer being curable andcomprising an amorphous material, the coating layer application devicecomprising: a heating device being configured so as to (i) maintain thetemperature of the coating layer within a temperature range beforeremoval of the transfer element from the coating layer, wherein withinthe temperature range the uncured coating material is in its supercooledliquid state; and/or (ii) partially cure the coating layer during acontact of the coating layer and the substrate and before removal of thetransfer element from the coating layer, in particular by increasing thetemperature of the coating layer to a temperature at or above a curingtemperature of the coating layer.

Described is a coating material, in particular for non-impact printing,the coating material comprising: a resin comprising at least one resincomponent, in particular at least one type of resin, the resincomprising in particular an amorphous resin portion; a curing agentcomprising at least one crosslinking agent and/or at least one thermalinitiator and/or at least one photoinitiator and/or at least onecatalyst; and wherein the coating material comprises the curing agent inan amount such that the cured coating material is able to reach a ratingof at least 2-3 in the Methylethylketone-test after 10 s according tothe DIN EN 12720; and/or the cured coating material resists at least 50IPA (Isopropyl alcohol) double rubs. The resin comprises one or more ofthe following: (i) a polyester resin component containing with respectto the overall amount of incorporated (used) acid monomer-groups, atleast 5 w-% isophthalic acid, in particular at least 10 w-% isophthalicacid, further in particular at least 25 w-% isophthalic acid, further inparticular at least 30 w-% isophthalic acid, further in particular atleast 50 w-% isophthalic acid, further in particular at least 80 w-%isophthalic acid, further in particular at least 85 w-% isophthalicacid; (ii) a polyester resin component containing 1 to 100 wt-% ofcycloaliphatic glycol compound with respect to the total weight of theglycol compounds of the polyester resin component, in particular TACD,further in particular TMCD; (iii) an acrylic resin; (iv) a fluorinecontaining polymer, in particular a hydroxyl functional fluorinepolymer; (v) a polyurethane resin.

Further described is a coating material being processable by non-impactprinting to form at least a part of a coating layer representing animage; the coating material comprising an amorphous resin portion andbeing curable; the coating material being configured for being appliedwith a thickness of at least 15 μm; wherein preferably the coatingmaterial is configured for being applied with a thickness of at least 20μm, in particular with a thickness of at least 30 μm, further inparticular with a thickness of at least 40 μm; the coating materialcomprising one or more of the following: (i) a polyester resincomprising at least one incorporated acid monomer and wherein at least10 weight percent of the at least one incorporated acid monomer isisophtalic acid, in particular at least 20 weight percent of the atleast one incorporated acid monomer is isophtalic acid, in particular atleast 30 weight percent of the at least one incorporated acid monomer isisophtalic acid, in particular at least 50 weight percent of the atleast one incorporated acid monomer is isophtalic acid, in particular atleast 80 weight percent of the at least one incorporated acid monomer isisophtalic acid, and further in particular at least 85 weight percent ofthe at least one incorporated acid monomer is isophtalic acid; (ii) apolyester resin containing 1 to 100 w-% of cycloaliphatic glycolcompound with respect to the total weight of the glycol compounds of thepolyester resin component; (iii) an acrylic resin, in particular TACD,further in particular TMCD; (iii) an acrylic resin; (iv) a fluorinecontaining polymer, in particular a hydroxyl functional fluorinepolymer; (v) a polyurethane resin.

Further described is a coating material for generating a coating layerby non-impact printing wherein the coating layer represents an image andwherein a resolution of the image is at least 100 DPI, the coatingmaterial comprising a curable resin; wherein the coating materialexhibits a minimum viscosity when being heated from room temperaturewith a heating rate of 5 Kelvin per minute up to a temperature wherecuring of the coating material occurs, wherein the minimum viscosity isin a range between 3 Pascal seconds to 20000 Pascal seconds, inparticular in a range between 50 Pascal seconds and 10000 Pascal secondsand further in particular in a range between 250 Pascal seconds and 7000Pascal seconds; and wherein a pill flow length is below 350 mm at apotential curing temperature which may be used to cure the coatingmaterial.

The invention claimed is:
 1. A non-impact printing device comprising: acoating material being curable and comprising a resin; the coatingmaterial comprising an amorphous resin portion in an amount of at least30 w-% based on the overall amount of resin; the coating materialcomprising with respect to the entire amount of coating material lessthan 0.5 w-% of flow additive; a printing unit, in particular anelectrophotographic printing unit, being configured for printing thecoating material so as to form a coating layer, wherein the coatinglayer forms at least part of a layer package comprising at least onelayer; the non-impact printing device being configured for providing thelayer package so as to define a surface structure with the layerpackage; wherein the surface structure is defined by a thicknessvariation of the layer package; wherein the thickness variation is in arange between 1 μm and 1000 μm, in particular in a range between 1 and300 μm, and is in particular more than 1 μm, in particular more than 5μm, in particular more than 10 μm and in particular more than 20 μm. 2.The non-impact printing device according to claim 1, wherein thenon-impact printing device being configured for providing the layerpackage with a varying thickness such that a first package portion ofthe layer package at a first position has a first thickness and a secondpackage portion of the layer package at a second position has a secondthickness; and/or wherein the printing unit is configured forselectively printing the coating material depending on a lateralposition in a plane of the coating layer.
 3. The non-impact printingdevice according to claim 1, wherein the non-impact printing device isconfigured for printing a further coating layer, in particular from thecoating material, as a part of the layer package and wherein inparticular the coating layer and the further coating layer have adifferent spatial coverage; wherein in particular the coating layer andthe further coating layer overlap each other, resulting in a thicknessvariation within the layer package; wherein in particular the coatinglayer and the further coating layer have functional groups which canreact with each other to thereby attach adjoining regions of the coatinglayer and the further coating layer; and/or wherein preferably theprinting unit is configured for printing of the further coating layer;or wherein preferably the printing unit is a first printing unit andwherein a different, second printing unit is provided, the secondprinting unit being configured for the printing of the further coatinglayer.
 4. The non-impact printing device according to claim 1, whereinthe non-impact printing device is configured for printing a coatingmaterial of at least two touching layers in particular wherein the twotouching layers include the coating layer and the further coating layer,in particular wherein two touching layers have functional groups capableof reacting with each other; in particular wherein the coating layer andthe further coating layer are formed from the same and/or differentcoating materials of a set of coating materials, in particular a set ofcoating materials which define at least a CMYK color system.
 5. Thenon-impact printing device according to claim 1, further comprising astructuring device, the structuring device being configured for imposinga height profile into the layer package, in particular by pressure, suchas by pressing an embossing element into the layer package, further inparticular by energy transfer such as the transfer of radiation energy,in particular by means of a laser beam, into the layer package toevaporate part of the layer package.
 6. The non-impact printing deviceaccording to claim 1, wherein the printing unit is configured forproviding the coating layer with a resolution in the layer plane of morethan 2 lines per millimeter, in particular more than 5 lines permillimeter and further in particular more than 10 lines per millimeter;and/or with a resolution perpendicular to the layer plane of more than 2lines per millimeter, in particular more than 5 lines per millimeter andfurther in particular more than 10 lines per millimeter and further inparticular with more than 20 lines per millimeter; and/or so as toestablish by the application of the coating layer a height difference ofat least 10 μm, in particular of at least 5 μm within a lateral distanceof less than 254 μm, in particular less than 85 μm and more inparticular less than 42 μm.
 7. The non-impact printing device accordingto claim 1, wherein a color in the coating layer extends continuouslyfrom a top surface of the coating layer to a bottom surface of thecoating layer; and/or wherein the layer package exhibits a thicknessvariation of at least 1 μm, in particular at least 5 μm and further inparticular at least 10 μm.
 8. The non-impact printing device accordingto claim 1, wherein the layer package forms an image on the targetsurface; and/or wherein the layer package includes at least one voidleaving the target surface at the position of the void uncovered; and/orwherein a smallest lateral dimension of the surface structure is above500 μm, in particular above 200 μm and further in particular 100 μm. 9.A reservoir, in particular a cartridge, for a non-impact printing deviceaccording to claim 1, the reservoir comprising a coating material forprinting of the coating layer; in particular wherein a reservoir contentof the reservoir comprises the coating material and the carrier; inparticular wherein the reservoir content comprises at least 4 w-% of thecoating material based on the overall weight of the reservoir content,in particular at least 6 wt-%, further in particular at least 8 w-%,further in particular at least 10 w-%, further in particular at least 16w-%, and further in particular at least 20 w-% of the coating materialbased on the overall weight of the reservoir content.
 10. A substrate,in particular a precoated substrate, comprising a layer package, thelayer package being cured and comprising at least one coating layer, theat least one coating layer comprising with respect to the entire amountof coating material of the coating layer less than 0.5 w-% of flowadditive, wherein a thickness of the layer package exhibits a variationin a range between 1 μm and 1000 μm, in particular in a range between 1and 300 μm, in particular more than 5 μm, in particular more than 10 μmand in particular more than 20 μm and wherein the layer package definesa surface structure; and/or wherein a thickness of the layer packagevaries over the substrate, and in particular wherein a first packageportion of the layer package at a first position has a first thicknessand a second package portion of the layer package at a second positionhas a second thickness; and/or wherein the layer package includes atleast one void leaving a surface of the substrate at the position of thevoid uncovered and/or wherein the layer package defining a surfacestructure, in particular wherein a smallest lateral dimension of thesurface structure is below 254 μm, in particular below 85 μm and furtherin particular below 42 μm; in particular the layer package having acuring degree that the image is able to reach a rating of at least 2-3in the Methylethylketone- test after 10 s according to the DIN EN 12720and/or the image resists at least 50 Isopropyl alcohol double rubsand/or the image resists at least 5 acetone double rubs, in particularat least 10 acetone double rubs, in particular at least 20 acetonedouble rubs; and/or wherein the layer package comprising a minimumarithmetic average roughness of larger or equal than 1 μm, Ra ≥1 μm, inparticular larger or equal than 3 μm, Ra ≥3 μm, and further inparticular larger or equal than 5 μm, Ra ≥5 μm; and/or a maximumthickness of the layer package being at least 2 μm, in particular 10 μm,further in particular 20 μm and further in particular 40 μm. 11.Substrate according to claim 10, wherein the substrate fulfills therequirements of Qualicoat class 1 and/or Qualicoat class 2 as defined ina specification for quality label for liquid and powder organic coatingson aluminum for architectural applications, 14 edition, approved on Nov.6, 2014 and effective from Jan. 1, 2015, available fromwww.qualicoat.net; and/or wherein the surface of the substrate comprisesa maximum arithmetic average roughness of equal or less than 1 μm, Ra ≥1μm, in particular equal or less than 0.5 μm, Ra ≥0.5 μm, and further inparticular equal or less than 0.2 μm, Ra ≥0.2 μm, where a definedsurface roughness of the substrate was compensated via an image of thepreceding features.
 12. Substrate according to claim 10, the layerpackage having a resolution of at least 100 DPI, in particular of atleast 300 DPI, and further in particular of at least 600 DPI; and/orwherein at least one coating layer has free functional groups capable ofreacting with other layers and/or the substrate in particular includinga pre-coat on a substrate to be printed and/or a top coat in particularbefore the curing.
 13. Method comprising: providing a layer package to atarget surface, the layer package defining a surface structure and athickness of the layer package, the layer package comprising at leastone layer; the surface structure being defined by a thickness variationof the layer package; and the thickness variation being in a rangebetween 1 μm and 1000 μm, in particular in a range between 1 and 300 μm,in particular more than 5 μm, in particular more than 10 μm and inparticular more than 20 μm; wherein providing the layer package includesprinting a coating material so as to form a coating layer, the coatinglayer forming a layer of the layer package, and the coating materialbeing curable and comprising a resin, the coating material comprising anamorphous resin portion in an amount of at least 30 w-% based on theoverall amount of resin, and the coating material comprising withrespect to the entire amount of coating material less than 0.5 w-% offlow additive, and the printing being performed by using a non-impactprinting method, in particular an electrophotographic printing method.14. Method according to claim 13, wherein the coating layer is a firstcoating layer, the method further comprising printing of at least onefurther coating layer by performing a layer by layer printing, whereinin particular each of the first coating layer and the at least onefurther coating layer has a maximum thickness of at least 1 μm, inparticular of at least 2 μm, further in particular of at least 4 μm,further in particular at least 10 μm, further in particular at least 20μm; and/or wherein layers of the layer package which are contacting eachother in a contact region have free functional groups to react with eachother in the contact region before or during curing, in particularwherein one or more existing layers are not cured or are at least onlypartly cured in the contact region before a further layer is appliedwhich makes contact to the contact region of the one or more existinglayers; and/or wherein the coating material is provided as a pluralityof particles, and wherein the coating material comprises an averagepowder particle size in a range between 1 μm and 70 μm, in particularbetween 1 μm and 25 μm, further in particular in a range between 5 μmand 20 μm and in particular wherein the coating material has a dl 0value in a range of 5 μm to 7 μm, a d50 value in a range of 8 μm to 10μm and a d90 in a range of 12 μm to 14 μm; and/or wherein a sphericityof the particles is at least 0.7, in particular at least 0.9 and/orwherein where the coating material comprises effect pigments with adiameter of less than 50 μm, in particular less than 20 μm and furtherin particular less than 10 μm and, where more than 50%, in particularmore than 75% and further in particular more than 90% of the surface ofthe effect pigment is covered with a thermosetting material which is inparticular not electrically conductive.
 15. A transfer elementcomprising a layer package, the layer package being uncured or onlypartially cured and comprising at least one coating layer, wherein athickness of the layer package is in a range between 1 μm and 1000 μm,wherein the layer package defines a surface structure, wherein the atleast one coating layer comprises an amorphous resin portion in anamount of at least 30 w-% based on the overall amount of resin, andwherein the coating layer comprises with respect to the entire coatinglayer less than 0.5 w-% of flow additive.